No one said everything has to be an E-Ticket. I personally believe that Magic Kingdom is at a point where refurbishments are almost all that is needed, aside from a couple replacements in Tomorrowland and Fantasyland (on top of Fantasyland Expansion). With that said, I am loving the idea of a Tron E-Ticket, and so I would be incredibly happy if it happens (though it would be better at DHS). Another E-Ticket in Adventureland might help, but I don't think it's necessary with two classic E-Tickets right there. Money would be better used helping whole parks with basically three E-Tickets than lands with two.
As for the other parks, I believe that the main focus should be one E-Ticket for World Showcase, another E-Ticket for Animal Kingdom (to absorb closures of Expedition Everest and Dinosaur. mostly), and probably an E-Ticket at Hollywood Studios. Other than that, Animal Kingdom needs a couple D-Tickets and a few C-Tickets, and Epcot and DHS could both use the same treatment.
WDW honestly only needs about 5 new E-Tickets, as well as a few D-Tickets and C-Tickets and a whole lot of refurbishments. Now, even more E-Tickets might help to allow more refurbishments to occur, but Disney can definitely stretch a D-Ticket into an E-like experience. I remember reading that Toy Story Mania is a D-Ticket, but it gets advertised as an E-Ticket, and rightfully so.