For the record we have discussed this, and have not done it for all the reason you are mentioning.
First, we have to respect the players who have invested time and real world money, and virtual blood in their real estate. Merging would be a bit of a nightmare right now ...
Secondly, we have to think of benefit v. pain in something so expansive.
So for right now, in an "off expansion" dev cycle (notice I said Dev Cycle not Year), we are focusing on live and getting our core things fixed to try to drive players toward playing, and activity.
- Cal