I think, from the videos that we've seen and the features that are confirmed, that melee combat in particular looks to be less wonky than Warband's with its spammable feints and robotic attack animations. However, they have said that they are reducing the capacity to feint to some degree, and the new animations do not telegraph attacks as clearly as in Warband. Making your opponent more difficult to read should be something your opponent does, not something the game itself does. Cleaving is another major balance concern, and while I am not against it I do believe it needs to be difficult to achieve & thus situational. I am also concerned by damage & health values, as these are somewhat mundane things but very important when judging the efficacy of weapons, armor, and classes as a whole. Ranged combat is also an issue for me, especially as an erstwhile competitive player, because I'm in favor of retaining high accuracy on bows & crossbows while balancing them through other stats like rate of fire.
There's also the ever-present "khergit problem" which will be very much a repeat of Warband, IMO. Horse archers are inherently difficult to balance, and their state in Warband was considered too powerful for competitive play so they were always banned in tournaments. I'm certain that TaleWorlds won't just exclude an entire faction from their matchmaking system they have planned, so we will have to find an acceptable solution to this or just live with the fact that matchmaking will randomly be a joke at times.