As of now, we don't have enough info to make an informed decision. If I'm still playing WoW when Titan comes out (I assume I will be in some capacity, or at least D3, but you never know), I'm sure I'll give it a try. Maybe WoW will become f2p at that time, or they'll do a deal where one sub fee covers both mmos. At least that's what I'm hoping. If not I'll give it a shot anyway...probably eventually switch entirely because at some point they'll stop releasing content for WoW in favor of the new game.