Never mind increasing the raid size, let's see some X2 raids written into the game. Lots of them. And in order to prevent certain classes being written out of raiding altogether put in scenarios/challenges that require certain classes to be able to complete. Or limit amounts of certain classes to be able to zone in (ie this raid can only be undertaken by a force made up of minimum 2 fighters and max of 4, minimum of 3 healers and max of 5, minimum 3 mages and max of 5, minimum 3 scouts and max of 5).
Let's give those smaller guilds a chance to get involved with raiding without forcing alliances on them.