I've been designing maps for as long as I can remember...and while few of them have been published (and even fewer actually used) I know that they're some of the more accurate/unique maps out there.
Just reading through your arguments...and I wanted to pipe in what I thought about map making.
To represent hilly areas and mountain ranges you only have to think about what those actually do to units and cities. If the diamond is an area that is easily defensible, difficult to cross, and unproductive, I'd say that's a hill or mountain. If it's just "high" but retains none of those characteristics, then that diamond certainly couldn't be a hill or a mountain! More likely a plains square.
You may also use this sort of thinking to outline regions that are placed on greater projections when looking at smaller areas on the same size map. Forests may have clearings with plains diamonds or wet areas with swamp diamonds. Plains areas are traditionally grasslands broken with plains, forests, hills, and sometimes tundra. Mountains always have valleys or tundra and forests to break it up, etc. It makes the map look better and changes the effects of individual squares, making it more interesting when playing on it.
And for rivers you should just take a map that only includes rivers that are so and so important and only use the rivers included in that map. Makes it easy to figure out which ones to use.
That wasn't as much as I thoguht it would be...
