Meh, it depends on what you want out of your MMORPG.
WoW looks pretty damn good if you consider that the core engine that has been around for a decade and a half, but it's not a game you come to for visual fidelity if you have a powerful PC.
It's also not a first choice if you're super hardcore into either PvP or PvE on a mainstream level. There is still stuff to do for the core folks at the edges, but the main game (around which the bulk of the content is being designed) isn't exactly challenging in that sense.
The content drought between expansions is a problem that every MMORPG developer ever has faced, it's the nature of the beast (or: the product) quite simply. All you can do is manage your dev pipeline as efficiently as possible and come up with and adhere to a staggered release schedule that minimizes these droughts.
The more recent content drought is a symptom of resource allocation on a more global corporate level. WoW is nearing the end of the cash cow phase in its product life cycle for Activision Blizzard, they are reprioritizing accordingly.