So once leaderboards are fixed(resets and DCing not counting as losses) how about this:
Make leaderboards show only your wins/losses for the games you played after reaching rank 40.
That is where the competitive game really begins and both sides are equally matched, as people had time to learn what they’re doing.
It would also show who’s really skilled against good player/players, and not who might have gotten lucky against team who don’t even know how to play yet.
And, introduce weekly/monthly leaderboards in addition to the permanent one, so people can see who is the most skilled in a certain character at the moment.