An archipelago, a wetland, a coastal city, a forgotten coast, and a national park that presumably has lakes and rivers in it.
If you drew a box around the playable state, what percentage of that box is water you can be on rather than land you can drive on? I would guess higher than any GTA before it by a wide margin, and I think that has real consequences for how the game plays that nobody is factoring in.
Accepted answer
Higher than any of them by a distance, and I say that as the person who has been going on about water for two months.
My rough guess is that navigable water is somewhere between a fifth and a third of the playable area depending on how you count the wetland, which is not really water or land. That is a genuinely different game to build.
Consequence nobody is factoring in: if a third of the map is water then a third of the map has no roads, which changes what the map actually feels like to cross.
Airboats and fanboats being distinct named vehicle types supports that. You do not need two shallow water craft unless shallow water is a category of terrain.
The park will have rivers and lakes too. Everyone forgets fresh water because it is not the coast.
the wetland is the problem with your maths. is a mangrove flat water or land. the answer in real life is that it is whichever one is currently inconvenient
That is a genuinely useful complication and it is why I asked rather than guessing. Traversable by boat and traversable by car might overlap in the wetland, which no previous GTA has had to solve.