After Rich Geldreich of Valve came out a few weeks ago to write about the many problems with OpenGL, Joshua Barczak came out with a blog post to express his views on OpenGL: it's broken.
This developer with more than one decade of real-world experience argues that OpenGL is broken for a multitude of reasons. Among his reasons to classify OpenGL as broken as being highly fragmented across operating systems, the OpenGL driver quality is highly variable, OpenGL is inferior to its competitors, GLSL is bad, OpenGL threading is broken, OpenGL error handling is wrong, there's many inefficiencies, etc.
Joshua Barczak does acknowledge though there's some good qualities to OpenGL. This developer ultimately argues that OpenGL must be re-designed from scratch. "If Kronos and the OpenGL platform holders wish to become serious competitors in the high-end gaming space, they must be willing to [redesign OpenGL from scratch as Microsoft with Direct3D has done multiple times]." He also adds, "OpenGL must be augmented by a new industry standard which is, lean, clean, modern, and performance-oriented," to which he notes AMD's Mantle.
Read Joshua's post in full via his personal blog. Update: It's also worth pointing out that AMD's Graham Sellers says some of these complaints are invalid.