In prior versions of Frontier it as possible to generate maps with virtually no trees or thick massive forests that covered 1/3 of the screen as well as maps with massive mountains or maps devoid of nearly any terrain feature. This was because the sizes and amounts of every resource was chosen randomly and independently. So, it was possible to have small/scarce wood and small/scarce stone and small/scarce mountains, etc. all in the same random seed.
In this new version there are pre-set size/amount pairs ensuring that there are at least some resources with tons + small placements and others with big + normal placements. In other words, it's no longer possible to have a resource that is both tiny and scarce. In fact, all resources default to at least "normal". Players don't seem to enjoy randomly generated scarce resource maps.
The opposite was true of terrain where it was possible to have tons of huge terrain features and the map would take a long time trying to place all of these elements. Now, if we're going to place tons of terrain features, they are guaranteed to be tiny. And our largest terrain features are now big and they are guaranteed to be scarce.
The terrain height range was also modified slightly to create an even split between maps that generate water and lakes and those that generate valleys.