I understand the cross-posting issue, it's something that comes with a federated discussion format and I don't think anyone has come up with a great way to solve it without such a distributed effort. It's ironic that before when there were so few instances (before and during the first Reddit migration) there was a concern that without cross-posting a lot there wouldn't be enough growth and some communities might die out if they happened to be on a single failing instance. I'd rather have too much activity than none at all, at least you can filter or block the worse ones.