Symbian is already buttonless, it only has the menu button to take care of. And the problems you think exist, are gone. Symbian is on a whole different playing field. I had a play with a 701, pretty much flawless on that ARM11. Even though, the CPU is 2 generations old, the GPU more than makes up for it. It's currently the best in the market and is 1080p capable (software limited).

Nokia has taken care of their past mistakes, however, Elop didn't allow any of it to happen. He is either cancelling or delaying inhouse projects. Management was an issue in past development, and under Elop, it still is. Hardware, which was the main problem, has improved significantly compared to those GPU-less devices after the OMAP 2420 era.