Nope, it's possible to get loot. Even if you left at level one without ever leaving your base. Even though random is random, I really do not want the RNG gods to favor those who left.
And it would work pretty much like the current system. Only if a player was favored by the gods for loot who left, only then will the item randomly be given to another player who did finish the match. In the case of multiple players leaving, you may only get one additional item from a player who has left. So RNG will still be RNG, just not for those who decide to bail. Those who continue -may- get a reward which isn't even a given. But just to avoid nerdrage for when they do get items when they don't deserve them at all.
The filthiest shit I've seen is the Mirana mount (legendary) dropping for someone who left when he became first blood in the first 30 seconds of the game. I did not like that at all because there were 9 other players who definitely deserved it more instead of a deserter.