Wasn't Bulletstorm (had to force my brain to remember the name of the game) supposed to be the arcady humorous pseudo rip off of Borderlands? I didn't play it, and don't know anyone that did, but it had Steve Blum and lots of cursing I think.
Honestly though, I can't really think of a game that has ALL the elements that Borderlands has at the same time. I can list funny games with cartoonish cellshaded violence (No More Heros), games that are shooters but have skill trees/level ups (Deus Ex/Fallout), and games with lots of randomly generated loot (Diablo), but only one I know of that has all that and Moxxi's bewbs...I mean loveable Clap Trap -_-;
And they hold the world record, which the sequel is shattering, of the most guns in any game ever. If you just add in all the mods, shields, etc. of which there is waaaay more new kinds in BL2 they are pretty well blowing the loot benchmark away.
I mean in Skyrim you might find one of about 20 different kinds of the same 8 types of weapon, possibly with an enchantment. Ditto with armor/rings etc.
And the game just goes on and on and on, and I'm still playing it. My point is that they get away with having almost no incentive to actually loot chests and enter dungeons, compared to BL which can have something awesome literally pop up several times an hour that completely changes your playstyle because you found a sweet new item and wanna use it.
Its a "ooh I found a glass helm of waterbreathing to disenchant" vs. "I just found a shotgun that shoots rockets AND a sniper rifle that shoots acid. Guess I'll retire my alien lightning bolt shooter... ooh shiny!" (\(^3^)/)