That would help, to a degree, but there is a significant portion of the world where any of these actually proves to be more of a hinderance or a tactical annoyance. I'm with Joe on this one. They CAN be useful, but with how no two terrains types except for "artic" tends to stick together, even on really large maps, you can end up with units that you want to be useful on one terrain be utterly crap on attack, forcing them to attack you in your preffered terrain....which can be avoided by just walking past you.@Shoobs: My opinion is that all promotions within a terrain category should give combat bonuses to all the terrains in that category, so that "Arctic I" promotion gives just as much combat bonus to ice terrain as to permafrost, tundra, taiga and rocky cold (not a confirmed terrain yet.). Removing terrain damage should be how it already is though, so you need all arctic promotions to traverse the coldest (ice) terrain without taking damage.