Its as simple as that.
While I am a critic of the new system, I see your points. This is a teamgame, you want to enhance the team-aspect. Thats a good idea.
However, A lot of people enjoy the lone-wolf feeling of playing soloQ. You need to make a personal impact on your games, consistently, to rise through the ranks. This is the stuff the Legends in this community are made of. Faker makes a new account and rises within months to the top. People like that, people want to emulate that.
So, while you are at it making the dynamic groups happening: Give us a PURE SOLO QUEUE as well. No groups, not even duo, just solo queueing for 5v5 matches.
There really is no argument against that. People who wanna team up will have 2 options available, 5v5 and dynamic. Give the lone wolves, like me, the same chance to an experience that is tailored to what they want to experience in the game.
Oh, and queue timers are not an argument. It is simply unfair to treat me as a mere filling material for groups. If too few people want to volunteer to be the "fill up the group" - guys, then that's the groups problem, not ours.
If the queue timers are too high to be playable, that wouldn't mean that us soloQers are mean to the groups, it will simply mean that we don't want this system. And that's valueable feedback.