Speaking only for myself I play almost exclusively red side, out of my 60ish characters I think about 50 of them are villains or rogues. I like red side's content and atmosphere a lot but the lack of other villains is pretty noticeable. I think the major thing that red side lacks more than anything is content variety. While red side has some of the best story lines in all of CoX, from basically every contact in Sharkhead to the entire Destined Ones plot and of course the radio, I think it lacks variety within each of it's zones and it's got a very small number of zones compared to blue side. More content in general for red side would help improve player numbers there but that's not exactly an easy order to fulfill. I think in terms of the content I'd like to see would be more direct competition with heroes. Red side spends a lot of time setting up villainous plots for the the destined one only for them to fall through at the last act. If there was more fulfilling endings to some of those plots that involved opposing heroes, directly or indirectly, it'd be better. The Cult of the Shaper story arc is a really good example of this since it ends with the destined one(s) becoming super powered and taking on a full team of heroes, it's very good at fulfilling the fantasy of being the villain.