Well I wasn't going to even respond here, but since you've directly asked about it in a thread I was paying attention too, starting with traits.
Traits are one of the best new features this game has. They make roleplaying have an impact on gameplay, or from a powergamer point of view they force you to actually engage in roleplay. I don't think I'd ever even consider playing a cautious or blunt character, but with the trait system that's exactly what I did, and because of it I tend to feel like my characters are more "characters" and less "me". It's especially important since I'm controlling two characters. Odds are they'll be different classes and therefor want the benefit of different traits, so they end up diverging and becoming different characters BECAUSE of the trait system, when otherwise I would just roleplay them identically.
While I understand wanting the game to cater specifically to different paths of play, you lost me almost the instant you said "merge". You are trying to take out depth from the character system and turn it into a set path with hardly any choice, and I can't get behind that. There's definitely some bloat in the skills as it is, but nothing quite so drastic.
Tactician mode simply doesn't need an xp nerf. There aren't actually that many "extra" enemies, I don't think it even amounts to one whole level by the end of the game. It's still too easy, and there are other things that do need nerfs, but not the XP rate.