I would like to see some DLC that mixes things up a bit and changes the pace of the game, similar to how The Zombie Island of Dr.Ned changed the pace of the original Borderlands.
Finished Captain Scarlett earlier today, took me about 7 or 8 hours to do most of the sidequests and the main quest so it definitely has great value for money IMO. Really loved every second of it and can't wait to see what loot I'll get once I get to it again in TVHM.