Sadly, gameplay in my Tinker game has slowed. I have switched off into GMing my own game on alternating nights. This makes progression half speed, which combined with the slower leveling at the moment has caused me to only reach level 10 last session.
My love/hate relationship with the Tinker has begun to solidify a bit. Admittedly a large portion of it is due to playing a 3rd party class (which I recognize) but I'm starting to be able to form some words around it.
The class really needs to figure out what it is. Some of the prestige classes seem to try and address it, but for the most part I feel like they just spin off into something completely different. It needs to stop excluding vast parts of the game, there are things like aquatic adventures that the Tinker is royally screwed with. Finally there are tons of taxes, little things you have to buy and do to even have a viable minion.
Figure Out What It Is
The Tinker does a poor job of being a minion master, as it doesn't address the complete lack of danger each individual (or mass of) minions poses. A simple Dr 5/Anything will take most of the damage away from your crew, with an alpha potentially breaking through. Given that their primary damages are Fire/Electric with little to no customizing of this, any flexibility to avoid resistances/immunities doesn't exist. Furthermore said opponents with those abilities generally also have DR. Their base stats also suck, so they're pretty much subject to destruction once anyone glances at them so long as they don't have immunity. (after lvl 5ish, their hp pool is huge at low levels)
Furthermore, it takes a standard action for each minion to target a new target. You can take a Greater Innovation to make them all ATTACK the same target IF you hit said target with a touch attack as a standard action. There's also an innovation and an Alpha ability to help with this, but in the long run it’s VERY costly. You'll find you spend whole turns just stopping minions from attacking corpses. Or, since you activated an invention, you'll have to re-command them to attack an enemy.
A wizard or sorcerer with Summon Monster can probably outpace these guys pretty easily, with the added flexibility of some powerful spells. A Cleric's Spiritual Weapon out damages a regular minion by being force damage AND can summon. The only superiority they get is having buckets of HP sitting around on the battlefield impeding movement. If your DM determines enemy targets by rolling a die this is great. If it's by combat effectiveness, you can forget it.
Caster (Weird Effects Maker)
The Tinker does a poor job of having caster abilities. Their fireball is just plain worse in every way. Their potential stun ability in electroshocker is thwarted by any decent DR to electric, it’s a fort save effect (undead/constructs) and failed attack rolls (until around level 14ish it seems). They also have a severe lack of scaling and variety. You can basically sum up their powers to 'poor fireball', 'Ok single target Daze', 'overly expensive heals' (can inject potions). There is one main exception to this, which is the fly speed combined with saddle, which is just 'game breaking' in many cases. I guess it's arguable that the amount of times you can cast said spells is potentially huge (level fireballs a day and level x3 +3 shocks a day), but given you get only so many standard actions per turn and the situational nature of the spells, the value per Tinker action is pretty low in general. Oh and the only invention that scales without having to invest more Build Points is the Kamikaze. As anyone who plays a caster knows, that sucks.
An oracle or sorcerer blasts them out of the water they can’t even get a swim speed for.
This could technically go under Minion Master, but it's worth noting separately as there are MANY inventions that deal with it. The only minion with any chance of being good at maneuvers is the Alpha until around level 10, then if you focus, you are still worse than the fighter, which means it wasn't worth the effort. At around 15 you get an ability that makes you superior. The main issue you're fighting with (heh) is that regular automatons are small and have shitty stats, meaning you will pretty much never beat the CMD on a meaningful opponent. It takes a standard action as a Tinker (or alpha) per maneuver taken. At around level 10, you get medium sized automatons as a greater innovation, which still isn't enough to keep up, but around 15 there is an invention that lets you use a maneuver on as an area effect which makes you FINALLY superior. Since there's no real loss to buying inventions later, you can basically ignore maneuver inventions till 15 and just take them once you get said area effect invention (costs cash, but just like scrolls - scribing cost). Of course, at this point the wizard is reshaping reality, so maybe tripping, sundering and disarming over an area isn't as cool.
Fighter, Barbarian, Casters, they all have better maneuvers than you until a single invention is obtained. Getting two per turn means nothing when the fighter has 3+ attacks per turn.
With a class ability, and a set invention line, crafting should be a huge focus for the Tinker. That said, crafting in Pathfinder (and previous editions of DnD) sucks. What you don't see is the Tinker fixing this. Instead of a crafting speed bonus like the Alchemist, you get a bonus to crafting. Instead of minions getting decent crafting skills, they get HD to crafting (which is LOW). Since there's no caster level for a Tinker, you get no magic item creation, and the automatons DO get creation (Only brew potion and Wondrous Item) but with some heavy restrictions (cannot increase DC to ignore restrictions being the biggest) and using said terrible skills (spellcraft is not an option).
Anything with a caster level is better than you, and you will need them for your own crafting anyhow.
Skills and Actions
This is the biggest one. Let's go ahead and say that the ability to fly is off the table (still some concerns ON said table). It's in expansion content and requires an innovation (in other words a feat). Your minions cannot use skills without A: having the skill or B: the Tinker taking a standard action. Some fun facts: swim checks made every round are impossible for minions without swim skill, and with said swim skill, requires the Tinker tell them to swim as a standard action each round. Climb checks are similar. Once you get the skills (around level four) the minion's skills will probably be at +2, which means they aren't likely to succeed on any of them. At 10, I can get those movement skills up to a hearty +11 for 8 build points (hint, I only get 10 build points, so this is an unarmed minion until I spend the next 2). That said, why would I? I would have to sacrifice a standard action every turn. This pretty much excludes climbing and swimming adventures for your minion, and your alpha is going to have to sacrifice a lot of points to be viable.
Ok, so let’s ignore how stupid the minions are. Let's follow up WITH said movement innovation allowing for flight. (Note, minions will fall out of the sky the second they have to make a fly check) Aside from flight there are two other inventions you are granted. One makes your minion into a boat, this DOES give them a swim speed, but it can only travel on the surface, and shorts out if it goes into the water. Note: There is nothing that says minions normally short out in water. Going underwater isn't a thing until level 13, when they have limited diving ability in a very long description. Given you can have flight at 7th level, this is kind of ridiculous. The shorting out mechanic also doesn't make sense if you have elected that your minions are running on "the power of friendship" one of the suggested power sources.
Quite recently I had to dive into the underwater rules, and compare them to automatons. Firstly, since automatons use mundane fire, none of it works. Ever. So I hope you invested in customkaze, I elected for force dropping my 7d6 (additional blast charges) to 3d6. Note: All inventions that add damage to kamikaze denote a specific damage type, this means that that additional 2d6 damage is fire and therefore would be negated in water. Secondly, the aforementioned swim speed/skill issues. Finally, all the swim speed/freedom of movement buffs to counter negative effects from swimming appear to be single target, meaning you can look forwards to not getting their benefits for your minions.
In theory this is what minions are built for. With a strong 20ft movement speed, they're already lagging behind in most engagements. But whatever, it's just another disadvantage and calculation to add to the pile. But this isn't about the overland movement. Thanks to that cool innovation, now your minions can have a burrow speed! I have never taken this, I won’t take it ever, and here's why. Firstly, the burrow is only for soil. No stone, wood, and so on, so any really cool tricks won’t work. Secondly, let’s break down how directives work. Command a minion to do X, it does it, then waits for another order. So the most viable command would be an attack order, followed by the opponent BURROWING THROUGH SOIL. The automaton always takes the direct path, which would indicate burrowing would probably be the less likely choice. So let's say this happens. Now the minion has lost direct line of sight to the master, causing some fun effects. Effect 1, you cannot issue orders including but not limited to Halt! to make them come back and idle, and any other order to make them stop chasing the opponent. Effect 2: They lose the benefit of Master's Presence, turning them into a rather useless piece of fragile weaponry. Given it will be the only opponent, it will be swatted and life goes on. Fun fact, minion cannot actually see through said soil, so arguably they would not be able to pursue anything through it. So let's just ignore this invention some more then. Maybe if it could burrow through a wall it might be useful, but I dunno about that.
Magic Item Creation
Already mentioned, we gave the minions terrible skills and then made an even more crippling exception. We don't need this. Either choose to make it viable or don't. Minion gains craft wondrous item feat. Let them make whatever.
Here's an example of an invention tax, to have a minion fire a bow, you need to give it arms a quiver and martial weapon proficiency bow. This means you've invested 3 points and put down 3 lines to be able to use said bow. This basically makes it so ranged attacks are unavailable until level 3. And at that point you will have a small minion firing a large crossbow once a round for 1d8 damage (maybe).
The arms tax is the most egregious, but there are other taxes as well, without scaling inventions, many inventions require you buy an additional invention in addition to the original invention just to keep amping up the power. For instance craftsbot inventions, tools, arms, skill points, and class skills are all different inventions. And for a really shitty skill, it’s similar for all the skills. One invention to rule them all that levels up would do the job just fine.
Remember that bow firing minion? Yeah you gotta supply it with arrows. Same for alchemy throwers, potion injectors and poison applicators. Instead of just giving them a default low level effect and the OPTION to add more, you have to supply all of it. Since you can't do arrows until level 3 maybe it’s not so bad, but it's definitely been prohibitive for me regarding even considering alchemy effects... which would still be at normal damage so not too useful in mid to late levels. Now there is an invention that allows you to get a couple alchemy items for free... For 3 build points. At level 10 this is a huge amount of points to get two alchemists fire or smokesticks.
This is of course, not including the price of the alpha, which is grossly overpriced compared to a familiar.
Alright So What?
I am currently in a brainstorming phase of coming out with a fan expansion for the Tinker. After I decide I'm running dry on ideas, I'll start writing up potential characters with each invention set in some useful form (comparing it to level appropriate challenges), if I can't think of one, I'll nix the invention and move on. I'll be looking at each invention both at obtainment and later on. I’ll probably start this process this weekend.
I think I'll also consider working on an optional redo of some Tinker stuff, kind of an unofficial rewrite with a potentially more generally useful or focused Tinker ability. It will probably do away with or rewrite a number of Tinker inventions and hopefully tweak things to make them more playable. There might be some more unbalancing combinations, but I think I’ll break some stuff down that I have experienced or been told about.