All you have to do is get the average kdas for each player or their champion. If they queue'd for a role, then the champion pool selection is refined to look for their most played champions in said role. It can get a good idea of whether or not that player is good based off their w/r and kda. It's a very basic concept and what sites like op.gg and leagueofgraphs use.
Thing is those sites are using Riot Games League of Legends APIs to get the data in the first place. I mean, think about it-- the client you download keeps track of all of your inputs as well and sends them to their server which uses that information to sync up all the players in game, and possibly stores that data somewhere as well as all the ingame nitty gritty details such as where you warded, where you killed someone, who got firstblood, gold generated, etc.
The problem with this system is that match making is based off of MMR, not your elo. Even if auto-fill was eradicated(which it should), MMR based match making will still yield unhealthy/toxic/imbalanced matchmaking because it's based off some hidden value attached to each player and the average team mmrs. But the system doesn't try to match equal mmr players in each role. It's within certain set ranges, which probably has looser restrictions the harder it is to match players within a "desirable" time frame, meaning it will match drastically different mmr rated players in each role. I'm sure we've all experienced this.
I'm willing to bet most players are willing to have longer queues to get better quality ranked matches, and almost positive they'd love to do away with this hidden ranked system that completely obfuscates what elo you really belong in, and have a much more transparent system in place that lets you decide between two queues:
- auto filled, fast queues
or
- primary roles, slower queues
There are too many reasons why MMR + elo match making is not desirable, atleast in the way Riot implements it. That coupled with the fact fresh accounts get a much lower starting MMR and regardless if you win most of your placement matches still get placed at max low Silver. All of this is why a lot of ranked players are getting fed up with the match making and starting to really believe in "coinflip", "rigged", "forced winrate" match making because it really feels like they want you to grind ranked games.
Consequentially, it also destroys a lot more games in low elo as an unintentional side effect of trying to "prevent" smurfing. Now instead of ruining Gold-Plat games, iron, bronze, silver and all the way up are destroyed for the playerbase and further exacerbating the problem.
