PSA: Autofill is not an option
Not sure how many times I need to say this. It's not an option. Removing it wouldnt just "increase queue times by a few minutes". This is a basic production concept called bottlenecking. Let me explain it......again
Think of matchmaking as a production line. The players are the raw materials. The first thing that has to be done is selecting the right materials for the job. The correct quality (ELO) of materials are sorted together. Now there are 5 different stations (one for each role) that have to produce 2 units each before a final product (match) can be shipped out the door.
This is where the problems start. Well known fact: some roles are queued for more or less than others. However, for a production line to function at all, every station needs to be functioning at the same production rate. What happens when one station is slower? What happens when 4 stations make 1 unit/sec but 1 only makes .7 units/sec? You get problems. Big problems. Every other station starts backing up further and further and further AND FURTHER. This doesn't stop. In the real world, this halts the entire production line. In LoL we're talking 30, 40, 50, 60+ minute queues at prime time. Literally the ONLY limiting factor at this point is people getting fed up after 40 minutes and leaving queue. The greater the difference in production rate between the stations, the faster this occurs
So what does autofill do? Well, autofill insures that the production rate of each station is perfectly equal. If one station is falling behind, autofill converts resources from another station to make up the difference. That is why it's nesseccary. You CANNOT have a functioning production line working at full capacity if the different stages don't function at the same rate.
If you don't want autofill, fine. Let's go back to the old system? Let's remove all the stations and go back to sorting by quality (ELO) only. This is how the system worked when we had pick order. There are two ways to avoid autofill. One, equal amounts of people queue up for each role. Two, we give up role selection and go back to pick order.
SPOILER: you still get WAY more people forced into off roles with pick order than you do with autofill.
Oh and don't even try to pull "but there was no autofill in season 6!". If you're suggesting we go back to the dumpsterfire that was Dynamic Queue, kindly gtfo. We are not going back to the absolute worst matchmaking in LoL history hands down. There was not a second of any day where the Dynamic Queue hatred was plastered across the front page of these boards and Reddit. The system that got around autofill by deciding "three silver 5 players queueing together is the equivalent of Gold 2 MMR" is not an option. NEVER. AGAIN.