One turn a day also appeals more to a number of the people there. Apart from brief periods with other characters, the Colonies has been my favourite place to be for many years.
The balance of power is tricky, as once one realm gets to a certain size it does seem to dominate, but if other realms work together, that balance can swiftly be regained (and is generally what is wanted by everyone). It's not actually that long ago that Outer Tilog thought it was going to be wiped out.