I have not experienced a single crash, bug, or anything that you have described above. OWB runs fabulously for me on PC.
I will admit that I don't really use anything that the Update has to offer. I'm not a fan of the companion system, seeing as they always engage in combat despite the chances to sneak away. And I have already beaten all of the quests and things they have fixed, so it's not use to me.
Oh and the companion dismissal terminal is for companions in general, not just if they're in the Lucky 38. It's for when you lose your companions somehow and you need to dismiss them.
I don't think you're supposed to rate an entire DLC based on performance alone. It could be the best running game in the world, but if it svcks, it svcks. When you fix your crashing issues you should play the game on a good in depth level and come back to us with your findings.