After a lot of thinking, I've come to two good possibilities. The first is doing the same thing we did for Season 4, but encourage people to use other people's layouts (with permission) more often. That way, the number of unique layouts would decrease, and the number of episodes would increase.
Alternatively,we could just abolish the numbered season format as it is now, and simply list all the episodes made by individuals without numerical constraints. I'm thinking--let's take Olmec as an example--we'll have an "Olmec's Season" that has all of his unique layouts and episodes. And we'd have a "Mstrgmr's Season" and a "Carveyfan's Season" and a "Nicklegends' Season"... It would be like each writer has his or her own portfolio of episodes that isn't restricted by any means.
Man! There are so many options! But I'm leaning toward the second one right now. Any other thoughts?