I started my first playthrough after patch 3. There were some performance issues and bugs but none so major that they prevented me from playing or enjoying the game.
I don't want to say your experience is wrong, but my experience is that it is specifically patch 4 that actually broke the game. This also seems to be what most others are reporting. I would be happy to go back to patch 3.
I played into Act 3 pre-Patch 4 and it was beautiful (I wish had kept that save; I deleted it with the new updates because, supposedly, glitches were fixed and I tend to restart (probably habit from EA) my games to accomodante those fixes. It's only been this latest update that berked it up. Apparently Larian is watching the forums (I've been talking with one of the responders to bug reports) but they didn't have any real updates for me.
