Dynamic Queue games can never be balanced
If riot implemented dynamic queue for monetary reasons (e.g. to get more people to play ranked who would in turn buy more skins and whatnot) whatever, it was a bad move. If they did it to try and make the game better they were wrong. TBH their decision was probably a mixture of both. The problem with dynamic queue is that games can never be balanced; there are too many variables. Solo queue games could have matchmaking issues because of smurfs and other issues but DQ takes the cake in terms of being hard to create fair games.
1.) Boosting - Whether it is prevalent or not, it can cause serious issues in matchmaking
2.) Players of higher mmr used to balance out premades on the other team - This is just ridiculous. No one knows if the premade is casual or competitive and the higher mmr player could be a weaker player than other players in the same mmr range. The higher mmr player could also be boosted.
3.) Premades themselves - As aforementioned premades vary from casual to extremely competitive and a bunch of diamond+ smurfs can just jump on a silver or gold account and ruin a game for the people they are playing against.
There will never be perfect balancing and we shouldn't expect that. But DQ puts the terms "fair" and "equal" to shame because of its many competitive flaws. Riot has said that if they can make it so that games are as close to 50/50 as they can be for premade games, they will be happy. That is BS because 1.) it is impossible with the number of variables that dynamic queue allows, and 2.) the best option is for players of similar mmr to play against other players of similar mmr in a fair environment. Premades do not allow for a fair environment because of the aforementioned issues and the use of voice communication among other things. There is no ranked as of now in League. I hope they bring it back someday.