Much has been written about guilds having difficulties to move from 10-man Karazhan to 25-man raids like Serpentshrine Cavern, because of the difference in raid size. There is still some debate about whether the "entry level" raid dungeon is better if it is for a large raid size (like Molten Core was) or for a small raid size (like Karazhan is now). Both sizes have advantages and disadvantages. So I was wondering why World of Warcraft should be limited to have only one "entry level" raid dungeon.
Why does there need to be a raid progression for dungeon A to B to C to D? It is easy to imagine having for example two entry level raid dungeons, A and A', of equal difficulty and reward level, but for different raid sizes. For example one for 10 raiders, the other for 25. That way you choose your raid dungeon depending on the number of people you can get together. That could be followed by a similar couple of dungeons B and B', again of equal difficulty, but harder than A/A'. And so on. A parallel raid progression, where every guild could choose to either stick to the 10-man path, or the 25-man raid progression, or for casual guilds to do a bit of both.