Hello all.
I'm a former MUD (that's "text based MMORPG" for all you youngin's) developer. In truth, I was sucked in by the source code. It's well maintained, relatively clean, easy to read, and documented well enough to get into.
The only things I really would like to help add are:
1. Walls.- I have read the discussion on this one, and am confident it could be done well with minimal effort.
These two would add features required for other gaming styles:
2. Unit's eye view camera.- This would place the camera at the head height (First or third person views) as the selected unit.
2.a. Direct control over said unit.
(Okay, so I was a HUGE fan of the 'Posession' spell in Dungeon Keeper 2)
3. Inventory system for units.- This would be the most difficult to implement, as a large portion of code would have to be changed and added. It would allow for WC3 style heroes, and add another layer of game play.