I don't think Borderlands 2 approaches the same standard of wit or creativity as The Stick Of Truth, to be frank. Comedy requires discipline and a certain amount of subtlety, and that it something the former frequently lacks, sometimes hammering an intended joke home until it dies a painful death. Shouting, references and repetition just aren't very clever or creative to me. The first game made me smile and laugh multiple times with its surprisingly dark humour, but they went too far in the wrong direction with the sequel. So I don't think it's a masterpiece, comedy-wise. Mechanically, though, I love it. I could go back to it right now and have a whale of a time blowing things up. I think it's definitely the best game Gearbox have made in that respect.
EDIT: The Brutal Legend video was blocked from being embedded.