I've been eyeing OpenRCT2 for a while but this feature is what made me finally try it out. I think it has a lot of potential to attract new people via small scale real-word geography they know with rides based on places and events. With some imagination Venice could be represented by a Boat Hire, Niagara falls can be a River Rapids, etc.
Well I tried my hand at the southern tip of South America. The mountains came out great, but the lowlands are all flooded because the pixels are too dark and too similar to the ocean. (yellow lines are roughly the actual coastlines)
I'll try later to use some image editor to make everything lighter except the sea.
Anyway, this gave me an idea for a feature in the map generation process: "paint by height". You know how you can set the tiles as grass/sand/rock/etc? It would be useful to be able to change the ground type en masse depending on it's height. So for example if I wanted snow capped mountains I could turn to snow all tiles with altitude 45 to 50, and rock from 30 to 45. The game would do the bulk of the work and then the user does the finishing touches. It would come handy not just for height maps, but for anyone creating any map.
I made a mock-up for the interface: