That disencourage the random play specially in 2v2.
I think that we need a rework on ELO gain:
1-If you are playing random and your opponent is a team (and the match is not leveled (i.e you rank 50 and mate rank 700 vs a team rank 100) even if you get a loose you don't loose ELO.
2-If you leave the game within the first 15 minutes, you loose ELO.
I don't wanna be rude, but these changes make 0 sense and would be really bad to implement. There are many games out there already where solo queuers can get matched with people in a party (example: every single MOBA, or games like Counter Strike). All these games simply punish players for leaving early.
In Counter Strike, f someone is overall a nice player and rarely leaves, the cooldown is only 30 minutes if they leave a match (for the guy who said he had to run to get the baby, a weird sort of excuse to leave) - Someone leaving for their baby would only get 30 minutes. But if you leave again within a certain time, the delay increases (2 hours, a day, or even a week). If cry baby nerds who quit games all the time had to suddenly start having a 1 week time out where they couldn't play, I think that would probably fix the problem.
tl;dr This problem exists in MOBAs and Counter Strike, both of which already have found a solution