I've got similar ideas, but not entirely the same.

What you call communities would be closer to what I would call content sources / repositories (host servers) plus topic tags. Then instead of consensus (because that's too hard to automate with decent quality results) you'd have communities formed by subscribing to "curation feeds" which pull submissions and comment from all over the network in a similar style.

This would let you easily crosspost and comment to multiple related communities in a network, as well as to yeet bad mods/curators without losing any content or splitting the community (just create a new curation feed and get people to switch). You could similarly choose to have your client mix comment from multiple curation feeds (similar to "multireddits" on reddit).