From my experience, solo players have far more team oriented mindsets than premades. The general solo player is probly used to the old system where they have to be highly adaptable and ready to work with whichever members of their team is necessary to win. Premades on the other hand generally don't seem to care about anybody outside their premade so far. I can't even begin to count how many times a premade jungler ganks only for the lanes with fellow members of their premade in them while another lane could be playing highly safe and be pushed to his own tower making the perfect setup for a gank for the majority of the laning phase and never get one.
The biggest difference between premades and solo players right now is voice communication. The ability to spit out on the fly complex maneuvers is going to provide premades with far more potential than solo players can hope for. And since those maneuvers are so effective, they tend to be game deciding. When a game has equal sized premades, the victory tends to highly depend simply on which premade is better. Solo players have a comparitively limited influence on a game outside of completely throwing it.
For those of us who are used to our gameplay significantly increasing our chances of winning, dynamic queue is the biggest kick in the face we've ever gotten. Being the best player in the match means nothing if your premade can't keep up with theirs. And even worse, being a solo player drastically increases your chances of being on the team with the smaller or no premade against larger premades dragging your ability to win even further down.
