Modding

Map Editor

This needs to be easy to use and have lots of features like making RPGs and missions easily.

Unit Creator

You could choose from hundreds of different parts to make thousands of possibe combinations- There could be calculators to see if the engines could make the vehcle move or fly, and if the hull of the boat could support the weight of everything else etc.

This tool would make modding accesible to all.

After that you could chhose what the unit fires how it moves and what side it belongs to, what building it is trained out of etc.

There could be a feature where you create your own side too.

Model Converter

A intergrated model converter and texturer would be nice too, you could then use your own model and do the same to it as what you can do with it ingame ones.