It is tough to balance. Get the loot straight away and it doesn't feel rewarding. Get it after too long and it just feels like a grind.
Somewhere there is a sweet spot. Although there is the thrill of the hunt as well I guess. I got 4 Pearls legit on BL1 and each was just as amazing as the first to find.
I spend a lot of time on the game playing through story on different characters. Done 6 playthroughs at the moment. In playthrough 1 with Gaige and Sal. But when I'm on my 50s it's mostly just raid bosses, finding new ways to kill them, getting faster at it, correcting mistakes. I stream and record and stuff, so that adds to the experience as well.
Honestly? I'll be surprised if I'm not still playing BL2 in 2014.
I actually don't mind a grind. I tend to get distracted from a games main objective when I have the option of grinding for certain things. --- Oh, you thought they made this game for you? You clearly bought the wrong game.