I kinda doubt it's a simple change. These maps are basically hand-drawn in Photoshop or whatnot, and the graphics engine they're using (if one can call it that) simply wasn't designed as a Windows-native scalable display system, I'm guessing. So to convert it to scale to your desktop resolution would probably be a herculean undertaking, especially with all the interface elements and stuff that would go along with that. The UI doesn't use Windows dialog boxes/windows/etc. AFAIK, either.
For me, it's "ok" now, but I agree that we're facing something of a quandary. As we go on, no one is going to have a CRT, and most everyone is going to have widescreen LCDs. We're going to reach a point shortly where this game system or its follow on will have to change graphics technology. And yeah, I'd love to use all my monitor real estate and have a more high-rez game UI and map/counters to work with. But it is what it is, and what it is is still a damn fine wargame system. Fiddle with your settings (monitor/card) if you can and maybe you can find a setting that is workable for you. It ain't optimal, but it beats not playing.