Besides balance issues, you should fix the following issues.
1-You lose a game and you play from the start with less people than the enemy team (someone disconnects before the game starts for example and is not returning).
Than you lose and it gets counted as a loss.
And other similar less vs more members issues.
This shouldnt count as a loss.
Obviously it should count as a loss if someone leaves/disconnects, when they are behind in points. Otherwise you could abuse it.
2-You have a person in your team, who tries to lose on purpose.
You cant report him properly (the options in the list dont cover it well).
Someone in your team just goes afk for whatever reason.
No way to properly report either.
3-People who cheat.
Think of stuff like teleporting with hacks and such.
More action should be taken against this type of toxic behaviour as decribed in point 2 and 3. I dont get the impression, that much action is being taken.
Warnings, temporary banns and perma banns should be flying towards points 2 and 3.
Edit:
Making these changes is important to keep the health of the game well.