Is it worth it to come back?

Its been awhile since I've adventured through Azeroth. I joined a few months prior to the release of BC and have been playing the game up to early on WoD. My heart yearns to return to the world, but my wallet is telling me to move on. What has changed? Is it worth it to break bank to return back to the game I once loved, or is it a shadow of its former self?