Performance seems to be the best its ever been.
However theres no way in hell this is gonna be ready in 6 weeks.
Act 5 is pretty much finished but the other acts aren't, dots are completely broken, and theres so much general balance stuff that needs to be tested still (energy shield nerfs, life buffs etc). Act 9 and 10 aren't even going to be in the beta, no new skills or support gems yet either and they have to develop a new challenge league alongside all of that. I'm not a fan of act4 at all and that was rushed out a good month before it should have been, Kaoms areas were awful and were eventually shortened. Malachai didn't have a death animation for a few weeks, not to mention they really struggled with difficulty balance. You could argue that act4 cruel is still far too hard compared with merc act 1-3
I really hope they don't rush it out the door but they're a small company, gotta pay the bills sooner or later.