Hello,
That's a good idea, modding 0AD into a RoN 2. There are already multiple features from RoN appearing in 0AD, such as territory and diplomacy, so it should be possible to create a total conversion mod.
It's also quite nice seeing that RoN got a mention on the crowdfunding website as one of the classic games of the RTS genre.
~ Creator of Kings and Conquerors, a total conversion mod for Rise of Nations: Thrones and Patriots ~