I was able to reinstall Mesa just now.
pastebin is the output for glxinfo, which tells me I have direct rendering.
pastebin is the output for 'LIBGL_DEBUG=verbose LIBGL_DRIVERS_DIR=/usr/lib64/xorg/modules/dri/ glxinfo'. What caught my eye here are the following lines:
libGL: Can't open configuration file /etc/drirc: No such file or directory.
libGL: Can't open configuration file /home/gtl/.drirc: No such file or directory.
IRQ's not enabled, falling back to busy waits: 2 0
Despite erroneous as it is, i got around 930FPS on glxgears with the radeon driver.
So, thank you very much for the assist so far!