Signs are pointing to the release of patch 4.1 soon. While there's a lot going on in the first content patch of Cataclysm, there are no new raids. The reason for that is that general progression hasn't sufficiently conquered contemporary content; it's still a little too soon for a whole new raid tier.
But as with most things in the delicate ecosystem of WoW, you can't make many changes without those changes impacting other arenas of gameplay. There aren't new raids, but there are more than enough changes in patch 4.1 that raiding will be affected.
The biggest impact on raiding probably comes from valor point changes. If you're like me, you probably have trouble logging in every single day to accrue valor points. As of patch 4.1, you'll be able to run your daily random dungeons in batches. You can manage your play time without being forced to do a dungeon every day, as if it were some household chore.
This is a huge benefit to raids, since many raid members will now be able to pick up their full allowance of weekly valor points. More points translates into more gear, which will also translate into more progression. This is a change I've been hoping to see since Wrath, and I'm incredibly thankful to Blizzard for making random dungeon life more manageable.