I agree.
Cross-platform would also be a plus. (python maybe?)
i have found java apps to be really resource-intensive.
I am not too familiar with programming in anything but BASIC, and not very good at that. (I've never done any graphics with it)
The ability to export maps to jpg or bmp would be nice for printing, or import to something like rptools.
There is a "forgotten realms" interactive atlas that does a fairly good job in its limited way, but it is specific to faerun. And it's pretty big.