I liked RoN mostly because it was the only major RTS I had with a somewhat vibrant online community when I played (compared to Age of Empires and Empire Earth 1, anyway). Then GS killed the servers and the HD version doesn't seem like an improvement.
RoN always had a lot less variety than other RTS games in terms of scenarios. AOE and EE both had diplomacy style build and destroy, pseudo-RPGs, cinematic type games, etc whereas RoN was always basically just "build cities and conquer stuff", occasionally "conquer cities because you can't build more", and if you had enough friends online, "use diplomacy with your friends and paint a map your favourite colour".
I also got a chuckle out of how age advantages didn't matter as much compared to, say, Empire Earth. In RoN, you could conceivably fight someone in the Information Age with Industrial Age troops and come out okay because of how weak everything felt (with the exception of nukes), whereas in EE, if you went against a Nano Age army with a Modern Age army you'd probably be taking at least 3-1 losses, a fact exploited by a few campaign missions. About 10 Nano Age regular infantry and a tank could easily kill hundreds upon hundreds of Stone Age cavemen without taking significant damage, whereas in RoN a bunch of phalanxes could actually inflict significant losses on T51 tanks.