I think that wow>l2 and any other mmorpg but all mmos steal some ideas from each other. Blizzard dont need to steal many ideas because it release a new version once in a while and make some nerfing to OP chars and some weak chars more overpowered (thats the reason most ppl quit wow, at least some friends of mine who use to play wow). For example Aion from Ncsoft is a mix of wow and l2 and maybe it have some features from other mmos...