Improve rebalance speed of small dataset

There are a few but very common rebalance use cases that our customers and prospective customers are performing which show very slow speed and then lead to a poor perception of the software's performance. At larger scale, the rebalance speed can be easier explain by many items and lots of data

These use cases include:
-4 nodes to 6 nodes with 8k ops/sec on one of the beer-sample database with the gamesim sample database installed but not under load. This is the demo that our sales team gives on a very regular basis.
-1 node to 2 nodes with an empty bucket. This is by far the most common, and our users expect that it should be very fast since there is no data...it's not very fast.
-1 node to 2 nodes with a small bucket. Same as above, only slightly less common

Ideally any of the above use cases should show the rebalance progress moving very quickly, and take no more than a few minutes (less than 10).

Let me know if there is more specific information required, or a need for an environment to be provided