It's not that stealth hasnt been done, it's just that the specs are very demanding and not efficient to micromanage. Combo points cap and so much goes to waste when you have a system that allows you to spend them early for a weaker version of the ability and/or lose the extra earned when at cap. Running moonkins is a popular way to get around that problem, though they arent the best in vanilla. 5 Hybrid resto/balance would be one of the best pvp teams imo.