The first of the refinements being made is that we're combining all raid sizes and difficulties into a single lockout. Unlike today, 10- and 25-player modes of a single raid will share the same lockout. You can defeat each raid boss once per week per character. In other words, if you wanted to do both a 10- and 25-person raid in a single week, you’d need to do so on two different characters. Normal versus Heroic mode will be chosen on a per-boss basis in Cataclysm raids, the same way it works in Icecrown Citadel. Obviously the raid lockout change doesn't apply in pure Icecrown terms though, as this change goes hand-in-hand with a few other changes to raid progression in Cataclysm.
Ok so this is the fix proposed by Vox Immortalis in their recent interview on pwnwear.com, where they talk about sharing the lock so guilds can only do one format or the other. Not being able to run both raids in the same week will have consequences.
I hope this change means less emblems to grind per tier piece. Blizzard said they currently balance the cost of Tier 10 around doing both 10 and 25 mans each week plus the daily heroic daily. Now if they balance around one raid per week less, that's less emblems to gather, which makes me happy.
For our 10 man guild this means no more pugging the same raid in 25 man any more, because toons will be locked to the 10 man raid. This means less loot opportunities and no more higher level loot for those who can get it, so we may not be able to overpower certain fights with twinked out toons. The single lock also means no running the VoA-equivalent twice for 2 tries at tier pieces, I know some guildies will go from VoA 25 to VoA 10 in the same PUG. This will of course slow down their acquisition of Tier pieces, myself I rarely bother with VoA due to its infuriatingly random availability.
The raid itemization is also interesting:
Dungeon Difficulty and Rewards
10- and 25-player (normal difficulty) -- Very similar to one another in difficulty; drop the exact same items as each other.
10- and 25-player (Heroic difficulty) -- Very similar to one another in difficulty; drop more powerful versions of the normal-difficulty items.
Charles talked about the disparity in items across the raid formats on Planet of the Hats. What is really exciting is this change means Blizzard have 1 raid to concentrate on itemizing properly for everyone, instead of sprinkling desirable loot over two raid formats like some sort of crazy purple pixie dust. This means I will have access to all the good loot for my class, rather than half or a third of it.
This change also means for the first time, everyone in a 10 man will be in the same level of gear. True, 25 man raiders may get more of it and maybe more badges, but essentially the gear level itself will be the same. Hopefully this means when raids are tested in 10 man on the PTR or in Beta, Blizzard can tailor the difficulty level properly as the raiders will be in the gear they expect for 10 man. Currently I get the impression the 10 man raids are done in 25m gear and thus sometimes tailored to be too hard for people in strictly 10m gear.
So why would you run 25 mans in Cataclysm? Blizzard say "25-player versions will drop a higher quantity of loot per player (items, but also badges, and even gold)". This is interesting and the fact that more badges will drop in 25m than 10m may mean 25 man raiders can gear up quicker through the Tier pieces on badge vendors. This may prove to be a motivation to continue with the 25 man format. I keep on reading on blogs that 25 man is a lot of hassle and some motivation to do them is the better loot, so it will be interesting to see how many 25 man guilds stick around when the loot is the same as 10 man.
Does this mean the end of the "strict" 10 man category? The gear will be the same and people will have the same chances to see the fights, what with limited attempts most likely not coming back. I guess if the number of badges dropping in 25m is twice that of 10m (to pick a silly example) then 25m raiders will gear up in Tier items quicker, so this may give them an advantage if they ever did 10 mans.
All in all this is a really good change for me and our guild, because we just run 10 mans anyway. Their difficulty should be tuned better, the loot should be better itemized and the cost of Tier pieces should be more attainable. Oh, and did Blizzard just refer to the emblems in Cataclysm as "badges"? Please can they be called badges in Cataclysm, "emblems" is all very well but doesn't lend itself to catchy badger songs as much. Emblems emblems, mushroom mushroom!