With regards to memory fragmentation you would need to have the game handle is own memory management rather than using New/Delete or Malloc/free.
The engine used for Elemental and Fallen Enchantress do a ton of New/Deletes which, over time, resulted in a ton of memory fragmentation. This was to get around the 32bit memory limit of the day.
Since that time, we co-founded a company called Oxide which developed the Nitrous engine which we now use which handles all the memory management.
Eventually, when we return to Elemental, it'll be a new game that uses that engine.