Ah, that's right, I even knew of that presentation (and watched it again). I kind-of guessed that people were working on that (without any evidence other than "somebody noticed"), and I had no idea about how to fix that.
Moreover, there was work (from Antoine Pitrou IIRC) to change the policies of the GIL - it was/is released/reacquired every 100 opcodes (which might be ridiculously small or too large, depending on the opcodes), while A. Pitrou wanted to have some saner scheduling.
Releasing it every timeslice (i.e. ~80/100 ms IIRC) would probably help with the problems of that presentation - I should have another look to know if this makes sense. A simple user-level scheduler for GIL acquisition would maybe be needed in the worst case, but hopefully not.