Well the thing is, I have searched a little on the forums but didn't see this subject on the main pages, so if there was a discussion about it, I missed it.
If it is not on the main pages it must have been several months ago that this discussion took place and it couldn't hurt making the discussion active again
Maybe it couldn't hurt either to explain my suggestion further.
It could be that people think I want it on every island, that is not the case.
There are over 160,000 different coordinates, around half of them are oceans, that leaves 80,000, probably a little over 1/3 of those are islands, that leaves around 30,000 islands.
So what I am thinking about is that every half hour 1 island is set as a randomly hidden treasure island. If that island is not hit within 6 hours, the island will reset to normal. Something like that or lets say 1/500 chance that the island you hit holds a hidden treasure chest.
If the treasure chest is not collected back within a certain time, lets say 3 days, the treasure will be exposed to others hitting the island. So the islands can't be used as a long term storage system.
This means, if every hidden treasure island is found and occupied, a maximum of 144 islands will be used as 'storage', that is less than 1/2% of the total amount of islands. In case of a 1/500 chance, development could maximize the amount of islands which have an occupied treasure chest.
Of course if this % is too high or too low it can easily be adjusted to the likes of the development team by increasing or decreasing the timeperiod between the addings of a new selected island
Maybe it is also a nice addition to be able to sell your 'treasure map' in town, for lets say 75% of the value it represents.
Having a treasure map therefor has adventages and disadventages, you can secure a certain percentage of the gold you are carrying, but in the same time you have to be careful about your fame level and the distance you travel.