I believe that rank should be the basis of matchmaking, not MMR.
Again non-sence, match-making is either totally random or there is a MMR number.
Some games decide to hide the number from the playerbase, some games even does rated matchmaking but even hide vague ranks.
Or very rarely MMR is calculated as a temporary variable from scratch every time player joins the queue (from players history).
3. It is not the logical conclusion of my argument that all of the best and worst players should be on opposite teams from each other all the time. However that should be the case at least some of the time. MMR guarantees that it practically never happens, which is an artificially anti-competitive construct.
What evidence are you proposing that, this is not happening time to time in BL? It has been observed that if you are on a win-streak you start getting very unfavourable(according to player's current rating) games and rise really fast if you win these unfavourable seeds.
On a side note, Competitive Overwatch Streamers has taken accounts that were "stuck" in bronze/silver over a year and rose them up to Grandmaster before.
Finally, I have no idea if you are completely ignorant of "Game Theory" or gone mad because you studied it too much, but I would like you to define this theoritical (with mathematics not ideas) match-making system that does not include a MMR.
What is it? a State-Machine? a Neural Network? a bird? a flying man?