So here's a fun game a few guildies and I have when a new patch rolls out; count the number of things broken by the patch versus the things fixed by the patch. The results aren't stellar.
I would propose having a test server that everyone can play on that's made to test patches. Consider it a Beta server for new content. Here's a few initial thoughts I have on it.
First: Only one character per account can be on this server. This would keep down alts and multiple alliance joining, etc. This shouldn't be the place you play. The reason for this would be so that when you play on the test server, you're playing for giving feedback, finding bugs, and testing the play of the character you chose. You're not using it for playing the game like you do on the regular servers.
Second: Limited up time. To keep people playing on the regular servers, only have a test server up for a week or less. Take 1.3.3 update for example. Most issues with deployment were realized in the first 48-72 hours. 1.3.4 could have been rolled out to the NA/EU servers with much less complaints if there had been that window to live test the update.
Just an idea. I see a LOT of complaining on these forums. It's disheartening. Instead of having players react negatively to the idea you're interfering with their game, you could have a test server that instead creates the notion that players are helping the development process by finding the problems before they go live.