This is going to be a bit of a complex suggestion so stick with me.

So first I would like to adress some issues players talk on a daily basis:
"X has all the regions!!!"
"Regions are making X nation rich because its impossible for us to contest"

Ok so clearly you have heard atleast one of these once in ur ccnet journy, and this is how Im looking foward to fixing it.
The way to go here would be a tile region system such as the one shown in CampaignWar, Experimental Dev Plugin Blog #7, where you can see this image of Zaify in a ocean tile, that can get captured by ship battles: https://imgur.com/a/2Dn1vCp

This method would eliminate any type of complete naval domination since each nation would have to compete on a 1v1 basis for the same tiles, lets say for example, the nation of Imperium Romanum wanted to conquer as many tiles as possible, they would need to fight for those tiles individually.

How would this prevent mass domination?
Simple, a nation cannot defend such large areas by themselves, and even if they tried they would be met with multiple front attacks, that would quickly shut down everything, on the other hand, making in strictly a 1v1 nation on those tiles, would make so that players wouldnt be traveling 20k blocks just to help another nation in a tile, making it more fair, and more pushing towards the skill level, instead of just spamming allies to come and help defend X tile.

Mechanics of the feature:
- A tiles can be sieged during specific times, making sure some tiles have diferent times to ensure it is timezone fair to everyone, another thing that could be done would be vunerability windows for these tiles, since there would be lots of these, inputing a vunerability window wouldnt be a big problem.
- Tiles MUST be linked to a the nations ports, and to other tiles, so for example, if a straight line of Tiles from nation A was cut by Nation B, the remaining tiles that were "unlinked" would be put into wilderness, aka reversed to their neutral state
- A tile getting attacked must be made a 1v1 naval siege between both the defending nation and the attacking nation, making it fair, and preventing mass travelling from allies just to help on 1 tile


These tile mechanics could well be added in land, not affecting any town behavior but simply as pvp or movecraft tiles working the same way as naval ones, you may ask, "But what if some one has a town claiming over the whole tile", and that is a fair point, so I would argue that some areas could be put as specific tile zones, specially low, that is a gray area which I will not be going deep into.

With the addition of these tiles, Im sure there would be less need for sieges every week, so I would argue setting up sieges only once a month or so, because tbf, no1 should be speed preping a fort while on school, work, or general life, these tiles being more of daily wars would contribute for the need for combat in players

I may refer that, despite me not going deep into pvp tiles etc, they would be needed, and there would be a clear balance between these and movecraft ones, hope yall liked the suggestion, if you guys have any ideas or suggestions just comment