How raids will be changing in wow Cataclysm

As part of the large Cataclysm information released , we've gotten quite a bit more information on how raids will be changing. One exciting idea is "downshifting," namely, the ability to split a 25-man raid up into separate 10-mans. There won't be any sort of "upshifting" allowed, however. Simply put, if your 25-man fails to proceed due to numbers, it can break up into separate 10-mans with the same bosses defeated as the 25 was at the time of division, and if you later get those other players back, another 10-man can be created with the same conditions.

In addition,
raid lockouts will be more forgiving; as long as you have killed the same bosses as the raid in question, you'll be able to join a raid in progress even if you've been in a different raid to the same instance during the lockout. Basically, you will not be able to kill the same boss twice during a lockout, but you won't be totally cut off from raiding with others simply because you were in a different raid lockout earlier that fell apart, as one example.

Both these changes seem directly aimed at increasing flexibility in response to the shared lockout between 10- and 25-man raids in Cataclysm, and personally I think they go a long way towards addressing concerns I had with that concept. Anything that increases, rather than decreases, the available raid options is an improvement. In addition, "
There will be more 'Algalon-style' encounters for both 10- and 25-player heroic modes which will offer loot a half-tier better than the rest of the instance."

But there's more than just changes to raid lockouts and hard modes: We also have new details on two new raids coming with Cataclysm, Grim Batol - The Bastion of Twilight and Skywall.

The Bastion of Twilight is intended as an entry-level raid, with five encounters and an optional sixth boss at higher difficulty. The end boss is
Cho'gall himself, and apparently defeating him on heroic will trigger a floor-collapsing lore revelation described as a "horrifying secret" by Lead World Designer Alex Afrasiabi.

Skywall will feature a 5-man instance, Vortex Pinnacle, where you can use your own flying mounts to travel (but apparently no vehicle or flying mount combat of any kind) and a raid that will include players going up against
Al'Akir the Windlord.

All in all, a fair amount of new raiding information to whet anyone's appetite for news. I'm actually much happier about 10- and 25-man raids dropping the same gear now; it really sounds like the added flexibility will smooth out any bad patches in transition, and the new raids sound fascinating. What could possibly lurk under Cho'gall's floor?