[Sombre]

I'd really like to be able to mod darkvision as a value. I'd also like to be able to mod different forms in and out of water using unit numbers - just as the mermen, wet ones, capricorns etc have.

You could extend this to not just water but other terrain types - for example a unit which changed to a stronger form in a forest or a unit that gained flying when in a mountainous province (think gliders of some kind).