[nicktelford]

Your primary argument seems to be that in the event a "replication event" fails, the data is lost forever - this is simply not true.

I the event a replica is unavailable for a write, the co-ordinator stores that write itself and delivers it to the replica once it becomes available again (Hinted Handoff, see the oft linked paper on eventual consistency).

This makes read-repair far less of an issue, usually only as a mechanism to ensure consistency of requests that occur in the window between the node becoming available and the hint being delivered.

It's called eventual consistency for a reason. Writes don't just go missing. If you're uncomfortable with the "eventual" aspect of the replication model then you're better off with a database that sacrifices availability for improved consistency guarantees.

[grout]

Node failure is not the failure case in question. As long as the node is up, hinted handoff can't play any part.