AFAIK, all Erebus mapscripts have a lot of dividers, be it sea or peaks.
But if it's more sea and less peaks, then you have more targets for Octopus priests and more space for sea ports and more "Oversea trade" bonuses.
As for FOL economy, wouldn't elves be better for that by far? Ancient Forest town or Windmill is better than Ancient Forest lumbermill. Esus lets you have caster hero fast, which can have puppet-dominate fast, which lets you steal enemy army, instead of stealing that army's promotions.