As far as the graphics accelerator, PPC_DX, and games, all you need to do is take a look at the PC Gaming industry.
Thats actually a good idea. When the first 3d chips were released for PC (Virge3d and few months later 3dfx Voodoo and Riva 128) the industry picked them up very fast. A year later 2d games were virtually dead.
Now I hear that nVidia is building a graphics accelerator for the PPC, history has shown that Intel has had the slowest graphics chips on the market, so this already has made the Dell obsolete.
Guess you need to take a lecture on graphics chip history. PowerVR chips were always more efficient than comparable chips from NVidia. Tile based renderering is the way to go for mobile devices, since you do not make the chips as fast as possible, but as fast as possible given a power budget.
Also you can bet, that more devices next year will have an MBX core integrated, while i doubt we will see many NVidia based devices.