Matchmaking aside, there needs to be some sort of punishment or consequence implemented against people who DC(disconnect).
And I don’t mean the folks with poor internet connections and system crashers, as they usually come back or at least try to; I mean the folks who just up and rage quit, or who leave after seeing high leveled opponents because they want games where they can only win. 4v5 games are usually demoralizing; I’ve had the (dis)pleasure of having 4v5 in 3-4 out of 5 games. At that point, we can’t play to win, but instead just play to survive or just be a nuisance (though I will admit to having mild satisfaction in ending in a couple close games with a team of 4 against 5). It generally ends up being a salt fest for our side as 4 players are easily overextended between lanes, picked off, and killed.
I don’t entirely have a solution to DC-ing, but would like to suggest that the DC-ing players be punished some way to deter future rage or entitled quits. One way could be to give them a time-out of 30 minutes from PvP if they don’t make an attempt to rejoin the game they DC-ed from (this method has been used in MOBAs like Smite).
To balance the field in 4v5, one way could be to increase the buildable and minion stats (small and big mionons, turrets, boom cannons, healers) with each DC-ed player in a logarithmic trend (so as to plateau at some level between normal and annoyingly harder to destroy). I’m just throwing out random ideas here.