We had 20-man raids back in classic WoW -- two of them, in fact, Zul'Gurub and Ruins of Ahn'Qiraj. Neither exists as a 20-man raid any more, so this may seem odd to players who didn't raid then, but these were considered the small raids. People who had just spent hours raiding in Molten Core, Blackwing Lair or AQ40 would put together these runs on the fly to gear their alts or get a shot at off-spec loot, while other guilds that didn't have the numbers for 40-man raids would spend their time raiding these while trying to build up their numbers.
Why the extra quintet?
20-man raiding gave us some of the most interesting mechanics of classic WoW. We're all familiar with the Corrupted Blood mechanic of the Hakkar fight (it's even spawned sociological studies and inspired pre-expansion events), but fights like Buru and Ossirian were also, for their time, engaging and unique attempts at a new kind of raid fight.
The issue came when 40-man raids were scrapped as we entered The Burning Crusade. This was a decision that I supported at the time. Even though it hurt a few guilds, I believed it was overall good for the game. Where I was confused was in how the raid game in The Burning Crusade was set up. On launch, guilds formed 10-man raid teams to work Karazhan for gear in order to start on Gruul's Lair and Magtheridon's Lair, two 25-man raids with fewer encounters (Gruul's has two, Magtheridon has one). As a result, you ended up with either five fewer people than you needed to run three encounters, or five too many. Even keeping in mind that guilds often had two or three alternates per 10-man raid force, the difficulties of stepping up to 25s (the A vs. B team issues, different tanking requirements, a lot more people to keep track of) were compounded by the numbers game.
I really don't know why it was decided to go 10/25 instead of 10/20 when the 20-man raid was an established and successful type of raiding in original WoW.
As of now, most 25-man raid groups have the same number of tanks as 10s do, two dedicated tanks and an off-tank. This means that 25s bring more proportionate DPS than 10s do, and so 10-man DPS requirements can't be the same because there's a lower ratio of DPS to tanks/healers in 10s than 25s.
With less comes more
It would have been a lot easier to scale up raid forces from Kara to the larger raids if Blizzard had just doubled up on people. There would still have been issues with tank balance (do you want to go from two tanks in 10s to four tanks in 25, or is that too many tanks?), but the playerbase could likely have absorbed it more easily than they have the drastic differences in raid composition we see between the two raid sizes now.
There have been other suggestions for how to alter raid sizes. 15-man raiding has been suggested (effectively, tacking on a third 5-man group to 10-man raids, similar to the way Upper Blackrock Spire was run back in the early days of WoW). Other games cap party size at four and expand upward from there. I personally think for WoW, scaling from five to 10 to 20 makes the most sense and is easiest to implement. What are your thoughts?
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