Let's talk about the ranking system
Elo, is the ranking system originally created for ranking chess players the best way possible. It is considered to be 'flawless'. Here is where it gets tricky. LOL has adapted that elo ranking system for it's ranked competitive play however there is one thing that Riot didn't take into account, or they did but they had no time figuring out something better.
Chess is a very non-random 1 V 1 game and here is the real issue here. Chess has very few outside factors that may affect the outcome of the match. The moves are specific, the rules are too, it's a game that is solo and not group game so it's you against the other man. you make mistakes and you pay for them, if you are in a bad it's your personal problem.
LOL on the other hand is a team game, it consists of teams of people randomly met. In LOL there are INFINITE factors that affect the outcome. i will mention some here :
- one team gets 4 midlaner mains when the other one gets 1 midlane main, one support main, one adc main, ect.
- pick order is too random so a potentially good midlaner can be last pick when a crappy mid laner gets the lane as he is ahead in pick order.
- some people own a ton of champs to choose from while others only own a few.
- experience in the game
- runes
- critical hits and possibilities, meta champions vrs non meta champions, newly released champions.
- lags, dc, ping, afk
- flamers, ragers, ragequitters, feeders.
- What time of the day you play( earlier in the day you will be matched up with younger and less experienced players while later at night you will be matched with older and potentially more experienced players.
- duos vrs solo q
These and many more reasons are simply some of the reasons as to why LOL is way too complicated for Elo ranking system to be fair and effective.
Elo CAN be an effective way of ranking in 5 v 5 and 3 v 3 simply because it's kind a 1v1 situation as each team competes as group, but in solo queue it's everyman for themselves, and you don't chose who you are matched with.