Stealth for shadow is more of a convenience than a necessity. None of your major damaging abilities require you to be in stealth. The "rogue" class in this game is the scoundrel/operative.
As for gap closers: stealth, force slow, force speed are the main ones I can think of but my shadow is only level 25.
I like the look of this spec for PvP: http://www.torhead.com/skill-calc#601ZhGrRkhrbtzZf0c.1