Thank you, Cephalo! This is a great map script!
I have used the World Builder to generate a few test maps, and I greatly prefer setting the riverRainCheatFactor to 1.0. I enjoy seeing Mountains and Deserts act as natural barriers to expansion.
There were a few problems with this, however. Oases and wheat would pop up everywhere in dry deserts. A few oases are fine (I personally don't like the feature in any version of the game.) But they were popping up literally everywhere in the bigger deserts, the only rule was that they couldn't be adjacent. This seemed to encourage wheat being placed in the desert as well, which I found odd. I fixed this by simply removing the placement of Oases altogether, which is a simple fix (I just commented out the relevant line of code). However, I am sure that this affects your original map script with riverRainCheatFactor set to 1.6, it's just masked because there are so many floodplains. I was wondering if it was your intention to have this effect or not.
Regardless, it's a minor issue and a great script. I love the landmasses that result.