My largest problem with DX2 wasn't so much the unified ammo, or the console interface ... it was the lack of depth in the game.
DX1 had hours and hours and hours and hours of story. I remember that I played that game twice, and the second time took me even longer to play it than the first time. I found areas I hadn't previously noticed, or I set my augs differently to allow me access to certain areas earlier in the game.
I probably spent more time talking to NPCs in DX1 than I did shooting things. In DX2, that definitely was not the case.
Also, there was just something about the look of the first game. It looked ... austere, bleak, desolate. I hate to use the word cyberpunk, but insofar as that term is representative of the literature of Stephenson, Gibson, and other authors, I felt DX1 really fell into that mold. DX2? Not really at all, it was pretty much a scifi saturday morning cartoon.
If they can put together a deep story with hooks to the original game and a large world with complex areas of play, I'll buy this one for sure. Otherwise? It'd take some major convincing to play it.