Well you mean that 'walking on water' part? As someone else very disgruntled told me.
Well as a game design and concept here is the quandary.
Each nation will only DoW any or all of its 'immediate neighbors' which means a direct connection. And those land connections over waterways are just such connections.
As well, dead-end provinces and isthmus, and islands or island chains can be very problematic for the AI's. Ideally I would design a map where every single province had a least three connecting provinces. So there would be no dead-end for AI's to pile at.
With those considerations, you can eliminate all VP's in any province that is dead-end. That way AI's will not get hung up there. And generally that solution is not a bad one. However, the first issue of preserving the desirability of each AI country only DoW an immediate neighbor is more cumbersome to manage.
Example, Iberia is by location in a dead-end and only has France as an immediate neighbor to attack. Where France has Iberia, Flanders, Fed Germany, Italy. That is four to one, where Iberia always gets a clear shot at France one on one. Possible solutions. Abandon the DoW to neighbors only and push the AI's to more amphibious landings, this I ended up disfavoring because it seemed more ridiculous to have Iberia attack Mexico for instance, on and on across the planet, especially with no alliances with say Texas for instance.
Current game concept preserves the following.
DoW against immediate neighbors only, no matter the size of ones empire and suppressed AI alliance though not impossible for the human player. The challenge is when it is time to cross an ocean to get the next challenger.
In order to get the AI countries to leap across an ocean requires more than meets the eye. I have a solution for this I think though requires more testing. I have made it work with some situations.
Special note for those who might care. The reason I believe Japan for instance has no interest in attacking North America is because the far more plentiful VP in close-by Asia makes America a ridiculous target. Whereas I routinely could entice New Zealand using the exact same parameters to attack the West Coast over and over, sometimes taking and holding vast sections. As well, taking Hawaii Island, Wake etc on a repeating basis. As well even United Provinces of America would go after take those islands if at war with American West.
So, I do use land connections over sea following some visual logic of sorts.
To connect countries that are just across the water so to speak. Where it dynamically increases the variable of DoW and subsequent survival or empires that might consequently arise.
So with this logic I connected Iberia to North African Alliance so at least she can be in a two front war, this better gives France an occasional chance to become an empire. And many others as well, or just sowed them together better to give 3 to 1 stacking on provinces wherever plausible.
However, remember the connections are all located in a single file that can be easily swaped out back to vanilla.
With this I am sitting here starring again at the Pacific Ocean and thinking about how to deal with it better…
Edit: I already succeeded given the above parameters to get Scotland to DoW Canada. So now on to serious tackling of criss-crossing the Pacific Ocean.