Nobody is even hamming it up :(

Agreed. You think with such "insane mayhem™" you'd could just be silly and goof it up but it doesn't seems to strike a tone. Maybe it's just the editing of the trailer? I have found movie trailers editing to be worse and worse these days, they either don't tell you anything or just seem to hit all the high notes of the film.

Which is bizarre since the only memorable things from the game were the good design/voice acting for Handsome Jack, Tiny Tina, and Claptrap.

I'd throw in Ellie and her brother Scooter into memorable good design/voice acting , but yes totally agreed with your overall sentiment.