Would you mind clarifying your problems with the API? I've done a fair amount of work with OpenGL (mostly ES), and I've found it to be a sensible low-level target for my rendering engine. That's not to say I haven't run into problems, but I assume any high performance graphics API has a learning curve. I don't have experience with Direct3D or other APIs to compare with it though.
All of my complaints with OpenGL are related to, as jarrett mentioned, the lack of debugging tools and the fiddly cross-platform and cross-version issues.
All of my complaints with OpenGL are related to, as jarrett mentioned, the lack of debugging tools and the fiddly cross-platform and cross-version issues.