There are simply too many good options on the poll. The only one I wouldn't pick is a return to 3.5 because there are some well documented flaws with the system. The high level play issue is the most pressing, but there are others, such as the rapidly diminishing returns of iterative attacks, ultra-complicated grappling rules, issues with shapechanging, and the disparity in power level between the base classes in the core rules and the other classes that were released later, all of which I think Pathfinder is doing a good job addressing so far. If the final release manages to fix the high level play problem, then it will accomplish its objective, in my opinion.
But I wouldn't mind seeing a new edition that combines the core 1/2 level + ability modifier base for BAB and saves and then adds back in the simulationist elements of 3.5 that were stripped out. Then remove the powers mechanic and go back to the traditional Vancian magic and class abilities + feats to determine what your character can do. Keep 4E's methods for leveling up and down monsters and generating NPCs (in actual play, I used methods that were similar anyway thoughout 3.x, rather than spending the time to make everything technically perfect before a game). Finally, bring monster hit points back to 3.5 levels to make combat less grindy.
Make these changes and I'd be completely onboard a new edition.