Wouldent it be better if u can put an mmr limit. If ur 1800 player and dont want to play with people less than 1750 mmr, then u can type that as an request. I know the average wait time will be longer, but imo its worth playing a game you care about rather than games where the mmr difference is very large.
Net result would likely be everyone writing their own MMR as minimum to ensure that they only get matched with/against higher tier players, since that seems to be the goal for everyone. Which in turn would result in massively longer queues as the system has to individually handle the MMR requests of everyone involved.
In practice it would both be impractical and probably less enjoyable.
As much as I'd prefer to play with higher tier players, I don't think this is practical.