suggestion about commanders

About the ports : you should try the great "Elric" scenario made by Pocus aka Pythie. It is available on the illwinter pages. 3 large continents are linked by 3-4 ports each. Units in a port may freely move to another port, jumping over the oceans (the connexions are scripted in the .map file). Neat solution IMHO, only minor drawback is that flying units could 'jump' several oceans in one turn using those sealanes.
You'll also see navigable rivers, customized province names and special indeps.
Cheers