I tried making a lengthy post about this recently and was rebuffed, but I feel the point is worthy of repeating here on this topic.
If you compare this matchmaking system against more freeform systems (CS, Tribes, TF2, etc), the freeform systems have one critical advantage... player control. If a problematic situation arises (imbalanced teams, griefers, etc), the players involved have means to correct it. They can switch teams, change classes, or even quit out entirely if the situation is that toxic. As such, the most rage-worthy situations never actually happen or are naturally corrected by the playbase.
Due to the overzealous attempts to stamp out leavers, these options are currently absent in League. As such, this forces players to play out absolutely awful situations that should never arise in the first place.
As an example, one player queues while AFK, and then never joins the game. The game forces you to play out 20 minutes of 4v5... an absolute waste of time for all 9 involved.
Now I am not advocating carte blanche for leavers, and I am not advocating a change in the surrender time limits. What I am advocating are additional voting rights to resolve the most extreme, rage-worthy situations.
For example, in the above 4v5 situation, what if the players of both teams could collectively vote to dissolve the game as a draw with an 8 of 10 vote requirement.
These types of mechanisms would be a welcome relief from the common complaint of "this game is f*cked but we're forcing you to play it out anyway"