About mana-neutral attack: You are right, I took the bash upgrade that costs mana - that is when I started to realize that mana management can be an issue. Indeed, also the magician sometimes ran out of mana - which I found OK, as I expected that. Only later did I find out that even firing the bow costs like 5 mana (which is still a net +5 I think, I found that to be well-balanced). For the magician I would love some natural talent of hers like "regenerates +10/all mana when skipping turns" - that would make the mana issue more visible and also allow maybe to activly let her skip to use powerful spells afterwards.
About the buffs getting crowded: The stacking of buffs and effects seems to be a very important part of game mechanics, I remember the bleeding, poison and severall spells. For MOST of the time I could understand it well (tool tips work great!), but I got overwhelmed in time by combined (a) number of effects, (b) the high number of stack (c) their different behavior. Example: Bleeding does its damage at the end (?) of the turn, while the stacking damage spell of the magician does damage when it is cast, others do it under certain conditions. Well maybe the game is DESIGNED that way, but that is something that (at least for me) dramatically SLOWs the game down, the more complicated the effects become (because I must calculate a lot, what damage will happen to which character in the next turn or so). I am not sure that is intended. It might be OK for some BOSS fight, but I think that a mixture of different, yet less-complicated enemies might work well to keep the game fast (and still entertaining).