Really there shouldn't be such a requirement. This would allow Custom games to actually work the way many people want them to. We want to play certain maps or gametypes, not be held captive by the system. If Custom games can be made and filled from queue without requirement, it would be one major change for the better. Heck I'd log in regularly again. This should have been in from the start. Getting 10 people is unrealistic and only helps those with clans that have many people on. But what about after hours? What about players from different time zones who want to play certain maps but not put up with MM?
Maybe Muse forgot that when Quick Join was a feature, it was used constantly by new players to the point "quick joiners" was about as bad of a derogatory term as "Powder Monkey." But it was never used by veteran players. Removing the 10 player limit would not hurt the system as new or casual players would still join via MM anyways. It just gives vets or experienced players the ability to do what they always used to do, sit in lobbies to make matches they wanted to play. Lobbies return, match list doesn't, and MM happens at the same time. Everyone wins.