Agreed completely. This is by far the most negative thing about the expansion.  It becomes even worse when resources are set on 'rare.'

The reason behind that is that the global resource pool is shared between land and fortresses. This leads to most resources ending up in fortresses because they remain the most common facilities.

The number of resource facilities should be capped according to land/see ratio,  with stockpile facilities becoming more common to compensate for the reduction of resource facilities.

I agree with you : there should be more ressources on land.

The problem it's : the devs want to make the sea a feature what players must not ignore. So they decided to augment the ratio of ressources on the sea.

If they purely increase the ressources on land, the total ressources land + sea will be too high.

Anyway, I think in land there should be +20 % more ressources. And, in sea, a -20 % ressources may be replaced by others bonus (as more often super factories : influence, dust, or simply more science/industry/food reserves).