Nice review..!
Although I gotta disagree with vehicles, I loathed them in the first game, although over the extensive time I played it, I got very used to it, still terrible though... And I find it amazingly improved in BL2, although I still dislike mouse controlled steering, it make sup for it with the much improved vehicle physics, which for once don't make a full stop for hitting a rock or invisible wall, or just about any surface like in the first game, you can actually ram into things and crash horribly or flip the car in all kinds of ways, which in BL1 just felt coo arcade'y, as if you had a predetermined path meant for vehicles, and anything else would make you go on a full stop, which happened alot, ALOOOOOT, and apart from that, I just feel I have more control in general, I can actually chase enemy bandit vehicles, and not to mention the weapons on them actually kill stuff, which makes them more effective in combat, especially compared to how terribly awful and useless vehicle weapons were...
I also like how ramming enemies won't immediately kill them anymore, it felt so cheap in the first game, although they patched it, since when BL2 just came out, enemies would ragdoll all over the place when getting hit, I guess that made things too easy as well... Now you just do quite a bit of damage to them, or kill them, I really liked it when they ragdolled though, it was hilarious finding tough enemies and just lobbing them over your runner, haha, overall it's a fantastic game, and like you said, the writing and story in general, and characters as well are just a massive improvement from the first game, where everything was more like a hollow shell that was never filled with enough personality..! The DLC's for BL1 helped adding some, but BL2 just takes it so much further, and adds completely new ones really well too..!
Ps
It's great to hear you're enjoying it as well..!