There were (and still are) lots of places where PyOpenGL code assumed (assumes) that it is running GL. So far my cleanup efforts mean that on importing e.g. GLES1 you don't actually trigger a load of OpenGL. They also mean that most DLLs are lazy-loaded, something that means e.g. GLUT should no longer load on every PyOpenGL import. However, a lot of the helper code is still GL-arrogant, and that includes such basic things as the array handlers (which import OpenGL to get access to constants, etc) and the VBO module, which has a pluggable implementation, but imports the GL implementations directly on load.
There's going to be more code churn on this, but in the end the various APIs should each be usable separately; just a bug-fix, but a rather major one to make GLES support a first-class citizen.