Well until Universal sells the rights to Disney Marvel won't be happening in Orlando. As for Disney's future I wish I could share your hopes and dreams. Fantasyland is being constructed out of necessity and to increase capacity. In the grand scheme of things it's two d-tickets, a dual spinner, a play area, a top dollar food option, numerous meet and greets, and some snacks and shops. It's replacing one e ticket, one d ticket, a single spinner, a play area, meet and greets, and some small snack options. It's the least they could do to expand upon the worlds most visited theme park.
As for Avatar until I see a shovel in the ground and some initial plans I'm just not excited. Animal Kingdom as well as Epcot and the Studios should have all had major projects either open or under construction post Potter. Its been what 7 years since the last round of etickets opened RESORT wide. Potter phase 2 will open before Disney even answers, that's insane! Now with the public statements made by Disney about capital spending being cut back and Universal coming out and stating were greatly increasing capital spending over the next five years on top of the last 4 out of 5 years of increased capital spending I find it hard to get real excited about WDW's future.
One last thing to add before everyone thinks I am being one sided. I personally really enjoyed the mermaid dark ride and Disney does in fact still get my business. But it's actually the Disneyland resort that gets it. By this October I will of spent three times as much time at the DLR then the WDW resort over the past two and a half years. Here I come Disneyland to experience a true Disney expansion and Eticket.