I'd sum up my main complaints as follows(
1. (This is my biggest gripe) When a game has leveling in the mix it basically offloads gameplay balancing from the developer into the gamer. I'm not 100% complete type of gamer, but I've been hitting an ok percent of the side missions as I go along
2. The game has 75 bazillion weapons or whatever, but I don't get that amount of actual gameplay difference from them.
3. The times between the interesting combat setpieces just go on for far too long,
4. The act of looting is just kinda lame in general
1. Totally fair, it's easy to overlevel yourself - BUT, second playthrough fixes this from what I can see.
2. They're there, but the game certainly isn't clear on letting you know which weapons have interesting effects or behave in different ways. For example, I found a sniping shotgot, and a pistol with the fire rate of a SMG, a shotgun that sends out explody balls of electricity. Most rocket launchers behave in different ways as do most large machine guns. The way to look at it is to see the guns as more than the numbers. If you get one, and it's close to what you have, try it out, see how it feels. This would also help with the difficulty curve as you could be more likely to use a lower level gun that just feels right and matches the way you play.
3. This could be because you did so many side missions
4. I took a tip from Diablo and just started skipping all boxes that weren't big chests. The only times I open those other boxes is if I'm short on a particular type of ammo - but even then I'm more likely to just switch to another weapon. And you can also take it a step further and not pick anything up that isn't Green or better. The money you get from chests and white items is way less than what you get from good other items and you pick stuff up off the ground anyway. I don't feel short of cash in this game - where I frequently felt short in the first.
That said, everyone likes different things, I'm not trying to argue, just giving a different perspective on things