I accidentally found the culprit behind these insane long load game times...
In the game there are six harbor town/cities. Port Maje, Neketaka, Dunnage, Tikewara, Sayuka and Splintered Reef. These places have "supplies" button for purchasing ship supplies once the ship is in the harbor. I clicked on this button somewhere at the beginning of the game (I think in Port Maje), only to notice that I had no need for those kind of general ship supplies so I ignored these "shops" during the game.
Now I happened to once again click on this button in Dunnage and the game was frozen for nearly a minute. Then it listed all the items in the Dunnage's list and any further click would list all the item's again without freezing the game. And then I also notice that the save I made after that, was loaded about ~20 seconds faster. Thus I went to all six cities to use these shops. In three out of six (beside Dunnage... Neketaka and especially Splintered Reef) game was again frozen for about a minute, before listing the items. However, the saves I made after visiting harbor shops in all these six cities and any save further down the line, were loaded for about ~30 seconds. MUCH MUCH more bearable than over 2 minutes as it was before. So it seems it's not the discover of world map but discover of these harbor cities that slow down loading times...
How the heck did you do this...!? And also, why those ship upgrades like cannons or sails, are listed as 999+ items (assuming that has anything to do with prolonging loading times)? I also wonder if there are more oddities like these to further lower the times of game loading...
