Well, not a whole army. A single unit... the feature I proposed would prevent moving large amounts of troops, of course.
At least you cannot say it's unrealistic for a noble to hire a ship and crew, and ask them to drop him off anywhere along the coast, possibly taking along an infantry unit.
Sure you can. If the unit is 4 archers, then maybe not... But equipment is heavy, and cumbersome. If you couldn't find a place to dock, you had to send paddle boats to land. Horses don't fit, and the boats of the times weren't big enough to have 10 paddle boats on them. Consider all of the natural harbours as having been already settled by those port cities.
As for without a unit... well, coding restrictions, what can one say?
