the voice acting. yunas voice was absolutely terrible. she has a good voice, but the voice acting in general; the emotion, etc. was quite bad. wakka and auron's were perfect though.

something alse that annoyed me was the lip movement and facial expressions, actually it wasn't that bad but it could be improved.
but the lip movement was slow, i mean their mouths are still moving for like 2 or 3 seconds after they have finished talking.
theres probably a couple of other things too but i can't remember.