large accounts just sitting there

There is a feature, in game, that allows you to see if a player has been inactive long. Exodus.

A way to help the inactive accounts that will become active at a latter date is to setup a suspended account feature. I've played many games that use this and it should be reasonably easy to enact. This will eliminate most of the issues we're dealing with now.

This is the message you'll receive if you try to exodus too close to an active player:

'There are players within 10 squares of your intended destination who are neither in your alliance nor confederated with your alliance, and who either have logged in during the last 7 days, or have a population greater than zero and have logged in within the last 4 weeks; and your have not claimed Soverignty V on the square to override these restrictions - and this prevents you from moving.'

I have never tried to exodus too close to any players, active or inactive, but i'm guessing if an account hasn't logged in within the last 4 weeks you can do it.