For anyone who doesn't know what IMech is head over here.
Now that you're caught up, I figured I would start my thought process on a solution to this.
The game I'm making now WILL have plenty of social interaction. This could be court intrigue, inter-kingdom politics, demoralizing the opposing army and so on. Fortunately, I have already been considering a solution to this, it simply needs expansion.
Morale would be the hit points of social combat. This could be effected by the strength of the opposition, the force of will of the subject and more effects. However, unlike hitpoints, morale would require rolls against it to perform some actions, and perhaps could result in a fleeing before they reach zero.
Base morale would likely be a calculation of Leadership ability of leader (score written down on the character sheet. Likely a sum of the 'charisma' stat, perhaps a relevant skill and probably some form of level bonus) Reputation of leader (a higher reputation is something worth fighting for Training and short term modifiers.
Generally this should lead to npc soldiers fleeing in combat due to low morale then returning after their temporary modifiers return.
How does this apply to IMech? Well for one thing this is only a stab, not a coup de gras as it were. In this case it applies to mental and social skills effecting survivability. If your inspirational speech fails, will your troops route the second the other general pulls a dirty trick? If your intellect based strategy roll fails will it give the other troops a huge advantage?
But this is at a higher scale. How would morale apply to lower levels of interaction? I would say morale would have a huge effect in the common torture example. Your goal is to lower their morale. But where is the chance for failure? I would say getting information through torture is 'common' because the chance for 'failure' is uncommon. However I would also say that there is more than one check to make with torture, not only must you get the information, but you must either disguise your association with the torture, disguise the torture event itself, spin the torture as a clearly necessary act for the good of all, or take the full repressions to your more permanent reputation stat.
Alright, but how could your reputation be ruined in court? There are no tools of torture here. Easier I would argue, as your reputation is at stake with every button you push to reduce your targets 'morale'. Why in quotes? I would further define morale to be mental stability and control. This means if you are seducing, inciting or persuading, you are trying to destabilize or seize control of their mental state. Drop their morale and you will drop their control eventually they will have to roll against their morale or fall into your 'control'. Not necessarily being mind controlled, they will still have their self interest at heart. They wont jump off cliffs unless they think it's a safer option than staying on the edge. And failure? Making a fool of yourself in politics, being seen as an inept leader, these effect reputation and perhaps, reputation can effect persuasion.
Alright, so I covered interpersonal, and in mass encounters. But this brings up some thoughts on Reputation. Reputation would be a score on your character sheet, but I'm also thinking perhaps reputation traits would also be warranted. These would be positive or negative traits acquired from repeat occurrences of particular acts. Known for torture, known for being a womanizer, known as a drunk, known for granting mercy, known for his battle strategy and so on. This means in encounters where those matter (social encounters with women, encounters in the church, taking prisoners, morale of troops) you get a bonus or penalty as appropriate. This would mean, for all the spin you may put on your acts, eventually people will see the pattern.
There is of coarse more to work on with this, but for my system here is the sketch for the bones.