Slicing is great because the AH is so bad that it's hard to make any type of comparably cash with any other profession. Make sure you only take abundant/bountiful/rich missions and you should always make a decent profit.
I don't even bother trying to sell the schematics/missions/underworld goods I get from my professions now since the AH is so horrible. I just give them all to other people. I make way more profit from slicing than I could trying to play the AH at this point in the game.