Also, I'd like to have terrain PENALTIES, too. It think that would be nice - you might have a nice Class 10 world, but if half of the tiles are penalty tiles, it adds a big additional dimension.
I'd really rather not have this. It's already a pain to click through every last tile on a planet to figure out what the planet is best for, since the terrain type is only visible when the tile is selected. Having tiles that could negate the bonus from a structure, or even make it so that building a structure on a given tile actually penalizes the planet, would just cause added irritation.
Moreover, it's rather silly. Land reclamation has been a thing for a very long time; tradition indicates that the Cloaca Maxima in Rome was constructed c. 600BC to drain the swampy lands that occupied the area which became the Forum, so at least by tradition land reclamation has been around for more than 2600 years, and beyond the initial investment it's not that expensive to keep up. If the supposedly more advanced humans of GCIII have forgotten how to drain a swamp and so have to suffer penalties for constructions built in the area (aside, perhaps, from a minor additional maintenance fee to deal with settling and erosion), then I think there's a problem.
I also tend to agree with Gaunathor that a manufacturing bonus makes a bit more sense than a research bonus for an area which is rich in minerals.
