Dynamic Queue can be fixed with one simple checkbox
"Allow premades".
Making it essentially Solo Queue for people who want it, but without separating the playerbase into two queues. This way people who are OK with premades can be matched in both Dynamic games and Solo games, whatever is needed at the time.
If we don't want too many people to opt out of dynamic matchmaking to avoid just one of the problems (e.g. 4-man premades), make the full checkbox list customizable like this:
- Allow full team premades (Can't uncheck if you're a 5 man premade)
- Allow four-man premades (Can't uncheck if you're a 4 man premade, or 5)
- Allow three-man premades (Can't uncheck if you're a 3-5 man premade)
- Allow duos (Can't uncheck if you teamed up with other people)
Disallowing one of the options makes it unavailable for both sides. This means no teaming up with 4-man teams, for example.
Unchecking all 4 will give you a true solo queue, without even premade duos. To promote Dynamic Queue, allowing premades greater than your own may be rewarded with bonus IP or hextech loot.