Great video here that explains the complexity of pathfinding amongst other things, the team are Westwood were a bloody talented bunch!
The problem with that is it requires changing the AI and that could negatively affect the campaign. Improving the audio visual and adding some usability tweaks is one thing but adjusting pathfinding, etc is very complex and could fundamentally change too much.
Of course, now the source code is out I expect a ton of mods to do exactly that!