The population values are still pretty arbitrary, as are the region sizes and types.
We're looking at changing some of these to bring the values more in line with what we think is good gameplay.
I think the main problem is that when Tom originally created islands, he never though of balancing regions to begin with. You can see that from region distributions across EC and Atamara. Especially, EC where there are wealthier regions in the south while useless badlands in the north.
Rebalances that came after that increased the gap between the north and south mostly. Of course with the implementation of the coming resource system - which I highly doubt will come within a feasible time frame - this will mostly fixed.
