Opeth - can get repetetive, and the increasing Pink Floyd-isms in their newer material is beginning to worry me slightly...
Hatebreed - absolutely zero diversity in the songs. Sure, they're all brutal metalcore tracks, but if the next album doesn't widen their scope a little, I'm gonna get bored.
Nine Inch Nails - Stop releasing dodgy remix albums and get working on some new studio material, damnit!
Nasum - Hurry up and release that big collection of all your b-sides/split EP tracks/compilation tracks, I've been waiting for a year!
Napalm Death - when you play live, please stop grouping together all the 'Scum'-era tracks into a mid-set medley - they're good enought to stand up on their own!