I'd like Draenei rogues and warlocks, though it doesn't make a lick of sense lorewise, i think Blizz should just go all-out with the "Gameplay over lore details" thing by now at least where character class is concerned, in any realistic society there would be individuals who deviated from societal norm and went with the unaccepted lifestyles (or class) of their respective societies...
i don't know why a draenei rogue doesn't make sense. everyone needs infiltrators and scouts. the shattered sun uses them on quel'danas and as i said before, mishka with your team in pandaria. imo, it doesn't make sense for them to not be there.
Pandaren Druid just so i can be a REAL big fluffy panda.
Blood Elf druids and Tauren Rogues.
when all else fails, read the STICKIES.
Undead paladin and Draenei warlock are the only combos I really wish where there.
draenei warlocks are the only thing i'm really hesitant about. fel corruption is very fast in them. now, it'd be neat if they'd do it, but only allow variations of red skin with jagged horns. i'd do anything to get those color customizations >.<