This seems to be recreating a subset of what Riak can already do, and not as functional.
I’m confused by ‘LWW-element-set’ and CRDT. If you are alway taking the last timestamp then I’m not sure what CRDTs are adding.
Unless I’m missing something obvious, I think this could be implemented in Riak in about a day, and it would be more functional.
Maybe this link can give some context for you: https://developers.soundcloud.com/blog/roshi-a-crdt-system-for-timestamped-events
Yes, you can implement something similar with Riak, or Cassandra, or probably a lot of other data systems. But not with the same set of operational tradeoffs.
What are the operational trade-offs you are after?