The idea is that player have skill tree, which player can pick these skills with fame acquired in game, the same fame we get workers from.
Like we have kick, dodge, roll, enhanced vision, etc.. in our physical branch.
we have, power swing, parry, throw, etc.. for our mele weapon branch.
we have, power shot, fast shot, etc.. for bow weapon branch.
we have line, circle, turtle, arrow, etc.. formations in our army formation branch.
we can have Speech skills that will rise the companions morals temporally.
and many other type of skill that can put in medieval age context.
We have already RPG stats in game and i don't think having a skill tree would be out of context, it will make the game more fun, since i will be open skill like army formation and physical skill through out the game instead of having them open from start.