Ridges are kinda interesting strategically because they let you hide troops from enemy units' vision. In battle, they also create some areas where you can hide ranged units from Infantry, adding to the strategy involved in battle.

However, they are really awful for expanding and settling cities, as you get nothing from exploiting them and can't build anything on them. If you start out as the Cult, for example, in a foresty region with two ridges, you will probably have to Salt the Earth with your first or even second turn, in order to make it to a place where you can feasibly level up your districts. Nerfing you very badly. Moreover, they sometimes make some regions downright counterproductive for settling, if you also get some lakes in a "thin" region.

This makes for a rather hate-love relationship with ridges. On one hand, they create good gameplay for the combat aspect of the game (more strategically interesting battles, fun "hide and seek" aspect to finding enemy troops). On the other, they make for poor gameplay in the settling aspect (increased luck factor, regions that could be considered good for settling become bad)

There is a very simple solution however that would greatly weaken the bad aspects from Ridges: Just have them spawn almost exclusively near region borders You usually don't want to settle close to borders anyway since it makes your city more vulnerable to spies, and you can't exploit tiles in other regions anyway. Villages already tend to spawn near borders so it should be possible to code ridges in a similar way without much effort.

If this was done, I think I would go from always choosing "few" ridges in map generation, to choosing "some" or "a lot", and that might in turn would also make battles more fun and strategic for me, since there'd be even more terrain variety.

Plus, irl, I feel like large mountains and such are often what limits the extent of a city's "Area of Influence", so it would make sense.