Saw this already 100 000 000 times

I don’t think it is that easy. But a good feature would be if you could make backups from communities on other instances in case they go down. It would not save the pics, but you should use a third party image service to keep the hosting costs of you instance lower anyway. In the same way, you, but only you, could download a backup of your account.

Also a good idea would be a new protocol which allows syncing feeds/communities between instance, which effectively is mirroring.