So far every naysayer I've seen on this thread fails to understand the concept of a DRAFT teambuilder. It'd work like this: you roll into teambuilder, pick what ROLE you want, not what champion you want, then you get queued up according to the meta, so two bot lane, one mid, one top, one jungle. Then once you're queued up it's regular draft with bans and picks one at a time still.
The REAL problem with this system is that it 100% cements the meta. Sure you can still play your unconventional top laners, your "support" leblancs, your teemo jungle, you don't even have to play an adc/support if you're the bot lane, but the point I'm making is that you would still have to adhere to the two bot lane, one mid, one top, one jungle meta.
As for long queue times, they wouldn't be much longer than ranked games now because it'd be the only option. When the new come in, the old die out. The reason current teambuilder takes forever is because there are literally five different queues for the same game mode and teambuilder is the least popular of the five.