DA1 actually had strategy in it. Where you had to look and time things, move your guys etc. DA2, you still have to time things in order to hit the combos correctly and you need to move your guys out of the AOE, but other than that the strategy/tactical element is lost very hard. Especially considering that they took out the over the top camera view.
Secondly, skill cooldowns in DA2 are ridiculous, especially for mages. In retrospect, sustained spells have gotten stronger, but cmon, 45 secs on fireball spell? that does 1/10 of the damage a rogue can deal during that time. Where's the balance? mages have been reduced to support, because there's so much down time between spell casts that it isn't even worth it to build a nuker mage.
Lastly, the open world of DA1 had much better feel and setting than the singular city of DA2. Yes I understand that the story was structured so that it all took place in the same locale, but I wish they could spend a bit more time on the exterior maps to make them bigger and more unique instead of rehashing the same cave over and over. The deep roads part, laughable in its length, might as well skip it all toghether. Because it's nothing more than disgrace to present the deeproads with what bioware put in DA2.
TLDR: DA2 console game, while DA1 is a PC game. Lets not forget that RPG or tRPG started out on PCs with BG and NWN. Innovation to the mechanics is nice, but complete disregard for them is something completely different to innovation.