High MMR & stack abuse can be fixed using player psychology
Right now Phreak said there is little resources to go toward this problem, however it can actually be fixed with minor tweaks and players will solve it themselves.
Firstly we need a separate player mmr for solo play and group play but keep the queues together so groups still play against solos and queue times are not affected.
This includes a separate displayed rank for both solo and group play.
This is where players realize group mmr is kind of meaningless, just like flex queue in retail. After this change players queue solo and ranked integrity fixes itself.
As an added bonus you can queue with friends without affecting your solo classic mmr!
Thoughts?