It would be nice if DIST could conditionally use multicast instead of multiple unicasts when the number of owners to which to send a given command >= the size of the cluster. In fact, we could probably come up with some configurable ratio of the size of the cluster (perhaps as high as 50%?), above which it is more optimal to use multicast vs multiple unicasts. This would optimize the use of DIST in smaller, dynamic clusters.
With such an optimization in place, REPL would be completely obsolete.