Oh give me a break!Dropping the GL1 renderer right now would mean those Catalyst driver users with even the latest Radeon HD 6000/7000 series hardware would be faced by a challenging experience on the KDE desktop.
Martin said plenty of times on his blog post that dropping OpenGL 1.x wouldn't mean much for most of the people. There are XRender, and llvmpipe is in the works. Also I can use KWin without compositing, so not an issue here. And if I inevitably need compositing in KDE and Catalyst, I could always stick with 4.8.
I think the most interesting of all this topic is the little fight between Martin and a Fedora Dev for including KDE 4.0 in that distro.