"Redside... Best side? Right??" Yes. End of thread.
Seriously though, it always was for me. I could list why, but that's neither here nor there for this discussion. I can understand that some just feel some reversion to playing bad guys (funny, in an age when Grand Theft Auto can make billions, but of course that group of players doesn't necessarily overlap with ours), but I think ultimately that population is king. That's why even I'm mostly blueside today, and have been since the Live pop drop and Incarnate grinding leeched most people away from anything lower level. I like PUGing and find it especially needed as a low level toon.
What to do? I don't want to make red side Farmville, so I don't know if "bribe the players with more XP" or something would help. The Aeon task force is popular as all get out, but with people from blue side who switch to play then switch right back I'm sure; maybe gate that so you can't do it until after you've been red side for like 48 hours? Maybe gate Null him or herself? Aeon's still just farming anyway, essentially (thanks to speed runs etc.). I doubt that would really work... I guess don't have any really good ideas.