To be honest, I don't think we'll ever see a RoN 2.
Big Huge Games has been drifting away with Catan, The Asian Dynasties, and now this rpg. I believe in an interview Brian Reynolds, CEO of BHG, stated that they weren't totally leaving RTS's and PC games but I'm not sure about ever coming back to Rise of Nations.
BHG has a staff of a little under 100 - several of which are testers. There programmers are most likely too busy at the moment to be developing a RoN2.
I believe they may soon be working on another RTS, besides TAD. But looking at RTS Producer job available on the website, it sounds like it might be for the Xbox Live Arcade.
SourceContinuing to develop downloadable games like our upcoming version of Settlers of Catan for XBLA.
However, it also mentions the RoN franchise.[This message has been edited by Alex (edited 07-05-2007 @ 01:04 AM).]