I left my guild last night.
Don't really want to say much about it, except that the Guild Relations forum is right: If you are asking if you should leave your guild, the answer is always Yes. I ignored that advice, given to so many other posters, thinking that my situation was different. That was a mistake.
I'm not really sure what to do now. I could apply to another raiding guild. I could respec to Retribution and farm for my epic flying mount. I could wait for 2.4 and just do all the solo content. I could level an alt.
Ah well, maybe I'll use the free time to get caught up with posting.