The problem for me with DA2 is how much hp the mobs have in relation to the damage the team is doing. The fights aren't even tough, I'd say most of the deaths in DA2 were caused by friendly fire.
I think that along with the waves mechanic was honestly just an attempt to pad out the game time. DAO is a loooong game. DA2 is less so, which is understandable considering the truncated production. DA2 was only about 70 hours for me as opposed to the well over 100 hours for a DAO playthrough, but I would have been more than okay with a 40 to 50 hour game with better designed encounters. I imagine BioWare / EA thought many of their fans might feel cheated, though.
