I have an HBase table where items are keyed by a sequential row id. When doing bulk appends to this table, the last region of the table gets pretty large until enough compactions can be done to sort everything out.
In this type of case, it'd be better if when the region serving the largest keys doesn't split at the midkey, but on the last key. One way to implement this would be by saying that when the top region reaches MAX_REGION_SIZE/2, create a new region, with the lower half getting all the data and the top half empty. For bulk sequential inserts, this should avoid the need for any compactions.