Steam has it's last refund day today, if you're unsatisfied with the support, and the game's performance/content. I recommend going and getting your refund. Why pay for a game that you can buy half price when they fix everything? Or buy when the GOTY comes out?
This is just another attempt to piecemeal a game out to you, for $100+, a game that at least on the forums they are providing no acknowledgement of the problems, or any timetable for support.
If you're stuck playing other games due to the optimization here, why not refund and keep playing those games until it's fixed?