I agree with an earlier post that one of my least favorite things about MTWII are the innumerable characters one has to keep track of. And merchants create incredible amounts of cognitive dissonance for me: something as endemic and pervasive as trade is going to be summed up in a few merchants? Not bloody likely. Better to use them for something else, if at all. Perhaps they could be used as Regents? They were fewer and had more impact politically, afaik. Double as diplomats?

Princesses I can get behind. <ahem> Marriage-created alliances I think can be proven to have been very important diplomatic efforts, successful or not. Not to mention the off-spring caused huge upheavals in the transferring of power.

Priests, my secular humanism aside, are particularly troubling. Someone lamented earlier at suffering the use of them merely to watch some numbers move. I concur. Perhaps they could be changed into philosophers? A good example would be Archimedes at Syracuse: +3 morale for the garrison, +2 stars for the general, etc. It'd be like a moveable ancilliary.