If you want premade for CC you will have two possibilities which will lead to the same consequence: a decreasing pool of player after a certain amount of time as the public is not the same as MOBA.

1. you choose the same queue for solo and group => solo player will leave with time because of frustration and they will be fewer games
2. you choose to have two separates queues => the small CC player pool will be splitted in two and so fewer games for each group.

SE have all the data to see how much this mode is played. If too few people are playing CC they will diminish dev resources allocated to this feature. With time they will cut it and allocate resources elsewhere. I think that, even if the the current situation is not good, it's the least bad as silver buller does not exist in game dev.