For everyone moaning about the server issues, you do realise that all these people were trying to connect only on the American servers. There are another 2 regions that will open on release day. 300,000 people playing at the same time on one set of servers during a test weekend. You will have issues. They will be raising and lowering caps. They will be forcing us to copy paste passwords to ensure we don't completely crash the servers. I don't quite understand what people are expecting from what Blizzard freely admitted was a stress test.
In terms of gameplay, I had mixed feelings. Part of me liked that I couldn't nerf a character by putting my skill points into the wrong place (goddamn skeleton mages), but I did like those crazy builds you could get with full customisation. Although I think in the long run it'll add up to a lot more variety in builds as a lot more combinations should work. I liked the random generator adding more places to explore on each playthrough, keeping me interested when otherwise I'd have been bored a long time ago. The crafting system is like a much better gambling system. It has had no effect on my pre-order status (which I can't wait for).
Overall, I'm not worried about bugs, login issues, server crashes or anything like that when it releases. A game involving 4 different classes and 4 different people should have no problems given their experience with WoW. And if it does, I shall eat the DVD.