It'd be helpful if there was a better way to compare weapon statistics, and a way to autobuy your consumable items after every mission would probably help. A music track or two wouldn't hurt either. On the gameplay side I feel like some of the shotguns are a bit too AP costly to be worth the use and the game would probably benefit from a tutorial but that's about it.
All in all I really enjoyed the first game and so far this is looking to be a step forward in almost every regard. I'm loving it. The changes to the gunplay and item systems are a big step up. I do miss the sledgehammer though.