There already some very poweful 3d chips available on tablets / phones considering their size and power consumption. However I'm not really seeing the need for such powerful mobile GPUs because barely anybody is taking full advantage of them.
The apps that are making all the money are 2d match 3 and simple single tap games. Sure you have the odd infinity blade game and other games with a similar 3d graphics (GTA San Andreas, Max Payne)
but compared with games like wheres my water, candy, crush and doodle jump their numbers are really small. Infinity blade has all but disappeared from any apple charts but Angry Birds is still in the top ten.
Sure Creative Assembly could go and convert the full Total War to run on mobile instead of their cut down Shogun games but the number of users playing it compared to Words with friends would just not make it financially viable.