Don't call it a victory just yet. I don't have any crashes in the first boss on Normal, but I do have them on Vet.
Likewise, I managed to beat the final boss of the arena once without crashes, but now apparently it's impossible for me to do so, even after trying 5 times straight.
Anyway, gonna post in your thread, too. The more we pester Zenimax with this matter, the more chances we have of them actually doing something. Although I hope that U27 and the new memory manager fixes this.