I think it would be a great idea to have more water routes we could use to move, although it should take high travel times.
Sea routes around the outside of the continent would have been nice. I don't see any particular reason why they aren't available, other than a simple oversight.
This way a colonization of Darfix would be easier, but it would be also easier to attack big cities having sea connections.
Getting to Darfix isn't the hard part. That's probably the easiest of all the challenges.
