I reckon the feature that is missing is not the ability to pick and choose, but instead to automatically assign people trying to help preserve something to one

I reckon the feature that is missing is not the ability to pick and choose, but instead to automatically assign people trying to help preserve something to one chunk, with the idea of getting full coverage of the entire data set. If there are 100 pieces, and 500 people, you want each piece to be held by 5 people for 5x redundancy. And, if nodes leave the swarm, the system automatically rebalances which nodes are maintaining a particular piece of the dataset. The only solution being worked on out there that does this is IPFS https://github.com/jbenet/ipfs https://github.com/jbenet/ipfs https://github.com/jbenet/node-ipfs https://github.com/jbenet/node-ipfs https://github.com/jbenet/go-ipfs https://github.com/jbenet/go-ipfs