Performance requirements for certain functions/methods, Hardware Vendors might try hard to get certain functions of OpenGL running fast but then fall short with different/alternative functions. You could just add it as an additional OpenGL speed stamp. (as a simple example.. render 1000 smooth shaded triangles/quads/polygons/etc at a minimum of x, OpenGL does have the timing capacity, also it should be pointed out that theres a difference in the terms of performance between Windows/Linux? so opengl could have speed stamps for different OS's)
My main point is OpenGL leaves it abit too open for hardware vendors to mess up the performance of OpenGL.
And to V-man i am referring to loads more above, like dealing with images/animations, if glX is apart of OpenGL or released very closely then surely opengl could come up with image loading facilities easily. Rendering extremely fast/directly with 2D is important in any game, most have HUD's and GUI's.
As a question, Ive always been thinking about Rendering 2D stuff to one buffer and the 3D gameworld to another (at the same time) and then just copying the 3D to 2D and flipping the image to the screen but idk rather that would be faster? Not like id be able todo that since im using C++ with OpenGL and i dont know anything about graphics parallel processing.
Anyway as a bottom line for the actual API spec then OpenGL could really do with ensuring new developers have a much easier time with opengl functionality. Even if it means revamping 2D. It shouldnt be too difficult and frustrating to program with OpenGL. (Which is exactly how ive found it)