Can't vote since I don't even remember what the minimaps looked like before IV. And that's kind of the point to me - this is a UI element that you expect but it isn't something to dwell on that much, and that's probably why they kept it minimalistic. The minimap has very little functionality and it doesn't really matter how pretty it is. It shows cities, it shows influence/culture/borders. You click on it to move around fast. Does it really matter whether it's showing accurate terrain or not? Does seeing terrain on the mini affect what you use it for in any way? Not really. I do think the minimap in Civ 5 is alarmingly pitiful compared to just about anything ever seen before, but ultimately it has zero impact other than standing out for being so hideous.
What *would* have been nice would be to have a more GalCi2-like mini, where you can zoom it and isolate particular parts of the world and get more out of it, but I don't think any civ minimap has been more than just city locs and click around.