OpenGL might well be the "only truly cross-platform option", but it seems to me that, for games or mobile app development, getting stuff drawn on screen is only part of the problem. The rest is about doing so with the minimum use of cycles - either for better frame rates or better battery life. I can easily imagine that this is a classic 80/20 problem, with the 20% that takes 80% of the time being adequate ("butter smooth") performance.
So, given that the capabilities of the graphics hardware can vary a lot, how closely can a single, unified API like glnext approach optimal use of the hardware? And without the kinds of platform-specific code paths which are necessary under current OpenGL?
As long as there are multiple different GPUs around, there will always be a need for multiple code paths if you want to get good use of those GPUs, whether you use the same API or not.
Having a single, unified, inefficient base code path that you later optimise at hot points is invaluable to validate non-performance (i.e most) parts of your game.
So, given that the capabilities of the graphics hardware can vary a lot, how closely can a single, unified API like glnext approach optimal use of the hardware? And without the kinds of platform-specific code paths which are necessary under current OpenGL?