WoW has had the best MMO combat since it was released.
The closest to it would be what Wildstar put out and what they've been doing in Neverwinter Online - both of which had/have really responsive combat.
That being said there wasn't a lot of depth to Wildstar outside of not standing in the bad and the same with Neverwinter where all the classes pretty much play the same and there's not really a lot to distinguish a healer from a DPS or a tank for that matter.