With Oliver McFadden's Dante project, which has OpenGL ES 2.0 support, EGL support, a new GLSL back-end, and can now run Doom 3 on Android, there is now OpenGL desktop with EGL support.
In a recent pull there was work on "[Implementing] OpenGL over EGL api. The changes are minor and shows how clean the switch from OpenGL ES to OpenGL can be."
The code diff shows how easy it can be switching from OpenGL ES to OpenGL while sticking with EGL windowing system API.
While it's easy on the application/game side, there's still EGL/OpenGL bugs within Mesa to be ironed out -- i.e. this new bug for exposing OpenGL extensions rather than OpenGL ES extensions when using EGL.