People are abusing the report system to try get people banned so they don’t have to play with them. Since Blizzard clearly don’t read reports, or review any evidence for in-game actions to be reverted, it’s against Blizzard’s interests of banning all of their players because of pettiness.
Please increase the avoid list to at least 50. If players have the options to avoid more and more players, they’d do that instead of sending in reports for players playing badly or not playing heroes they choose (which end up getting banned anyway).
I don’t think people particularly care about waiting an extra 2-3 minutes longer for a match (since as you climb that happens anyway)… so increasing the avoid list is better for everyone.