I was thinking the same thing, but then a guildie who PvPs (I don't) pointed out a different view of it. The people who got GM/HWL got to be the elite few for quite a while. Now other people are getting the gear, but they didn't have it when it meant something significant. Now the gear is nice, but not amazing, considering the gear that will be available in a month or two once TBC is up and running.
If I was someone who actually did the GM/HWL grind right about now I'd be a little annoyed, the new system seems to be heavily devaluing their accomplishments.
As for guild issues in general, the guild I'm in is still clearing BWL and working halfheartedly on Naxx/AQ40. However, a lot of people are taking time off from raiding to enjoy PvP for a while. The result is that we'll end up with a few cancelled raids, but I think the guild will do fine.
On the other hand, I'm glad we keep raiding so we don't repeat the mistakes of other guilds on our server. One guild announced in October that they were 'cutting away the chaff' to prepare for a November TBC release. After the release was delayed, they tried to get their 40 man groups back together, but couldn't get a decent sized raid group. It seems telling almost 40% of your guild that you're abandoning them makes them less likely to want to raid with you...