Let's try to NOT make this a rant about autofill.

There is no explination required if you have actually encountered autofill, but if you do not know what autofill is then there is a link with a screenshot of riots definition. I could give in to the most common thing and rage about it, but that's not going to solve anything, instead I will simply explain why autofill is a really poor solution, and I will try to take most things into consideration as possible Let's start with the pros of autofill.

1. Shorter queue times People will match more quickly into a new game because all players techinically have a chance of just filling instead. This might be the only considerable pros I can think of, but there is a VERY GOOD reason for that. Queue times are quite exhausting for people that do not have a side activity. In lower elo than diamond 2 You will find queue times averagely shorter than higher than d2. The point is, that if you get frustrated and have a hard time dealing with emotions when losing, and you lose 2 games and both of them required a queue time of 30 minutes each, then it is comprehendable why some people just want to throw their monitor out their window for getting "cheated" not having enough playtime. I do like to think that most people that are D3 - Low master tier are still somewhat hardcore people that care about match equality and quality than queue times, but I guess that is a bit narrowminded.
2. Because people get another role than intended they play a champion they are strong at in order to make up for the void of knowledge for the role they are going to play. This may inspire off meta champions to be picked more often.

Now, too the cons of autofill.

1. It literally goes against the idea for choice of roles which was presented at the start of this season. And this is what puts most of the people on tilt, since they can finally literaly choose that they WILL play either selected roles. with a higher chance getting the primary role, if your primary role is a very crowded role then you should not be surprised if you do not get it unless you get your secondary role 10-20 games in a row (I can testify that). That is beside the point though. When people finally "settled in" into this whole system, autofill comes in, and then suddenly it gets awkward because you begin to question yourself: Did my choice even matter before I matched up?
2. It favours a specific groups og people and completely ruins the game experience for people who either are nuts for one champion ( one trick ponies) or people who have have dedicated their time learning their selected roles to the best of their ability. Those people can main 10 champions for their 2 roles, but suddenly. in point 2 in pros, I said that off meta champions could be picked, but most of the time this could be a champion that is disadvantageous for the team, or maybe they do not have a champion that they "can play" because they simply do not play that style of champion (You do not play tanks in an adc role for instance). But for those who have adapted better into playing 2 specific roles just gets unjustly punished.
3. It encourages trolling, tho that this is minor because of the tweet of getting permabanned for breaking a conduct, people with multiple accounts couldn't care less. And the reason I bring it up is because I have had a report "acknowledged" but the player somehow is playing. I will make another post about it so that it can be fully investigated, since I am still not sure wether I need clarity or if this person is just overlooked.
4. Getting 25 minute queue times and still getting autofilled a role which you did not desire, and this one kind of defeats the purpose of autofill doesn't it? but I don't think there is a very complicated fix too it, or atleast from my perspective because I do not work at Riot games, and neither do I have any backstage deep knowledge on how matchmaking works.
5. Hardcore gamers prefer quality over quanitity in games, depending on how much they like the meta and how they adapted, the most important thing is that they get matched of equal skill rating, theoretically, if a player intentionally feeds because it isn't his day, that specific person will still lose rating along with his team since this is a team game. When a person that has had a bad day already is in our game is out of our control to fully know if he is going to lose the game by himself, and there is no foolproof way to prevent that unless you make something like a daily survey asking how the current gamer is feeling and consulting him on what he should play. As stated, it can be annoying, but how else are you going to get an answer? Atleast the effort of maximizing a game was done instead of just having a higher chance of quickly coming into a game with outrageous poor quality.
6. Players who recently come to the "autofill elo" Might already have a lot of games where they have had choice of role. When they suddenly get this autofill thingy, don't you think that it might catch them by surprize? This will be even worse for the people for the future since they are simply not even used to the fact that autofill is active.
7. Motivation, I mean, don't you think there will be a slight decline for high elo players to play and enjoy quality ranked games? I know too many people that have more and more alternative accounts that they play on which isn't even for their skill level.

When all this being said, i have to apologize for my grammar mistakes and maybe even incomprehendable sentences, but if someone wants to correct me I'll gladly edit it. Also, it might not be a big solution, but maybe showing a general population of the people that are playing might improve match quality in a sense for showing a wide variety players currently playing. It might lose league some face when it shows how many people can be off and online, but if more people play at the same dates, then we might be able to find better matches! it might not have to be who is currently in queue and what not, just as long as it shows all the people that are currently on pc's (non mobile) that can play League who is online!

Thank you for reading! let's me know if there are any other pros too autofill that I might have missed because in my perspective the cons overflow. Also, I would like to have all people who are currently experiencing autofill atm write a comment or 2 about what their thoughts are.