Autofill is too punishing towards our MMR.
Specifically towards climbing if im currently in a win streak winning from a role im winning games from, it does not help at all to autofill me or someone else into a match where they are playing an off role such as support 99% of the time and have no control over the game. According to your forced philosophy everyone must be at heart a support or other auto filled role when at heart we are all different and have different high and low ends towards performing in various roles.
For example me i am primarily a jungle player now and lets say for 7 out of 10 matches i am winning in my division on average 7 wins per 10 matches meaning if i continue to perform that average i will climb it is obvious that anyone would eventually climb performing that average.
But with the autofill in place it influences the MMR system if the system was currently convinced that i was outperforming steadily. Then the autofilled match where i lost only lies to the system stating i deserved to lose that specific match because the system was already guessing i would lose that match due to the ruberband MMR stretching from my 4 - 5 win streak.
Putting me in support basically guarantees the loss where as if i had gotten my regular role i could of extended my win streak further proving i belong in a higher division based on my raised MMR from winning consecutively.
And that's why auto fill is not your friend and is complete bullshit for this season.