Redside is better, has better stories/content. But it's also harder.
Most blue players hated that fact. They didn't like the struggle. When Redside content started to show it's head on Blueside(Mobs/Mechanics). OMG, the gnashing of teeth back then. I found it utterly hilarious. As when Red came out, I was 95% over there.
I will remember to this to day, cuz I bout pissed myself laughing so hard, But Blueside SG on Virtue came to red to do stuff, omg the crying in broadcast about how hard it was on Mercy Island, with Longbow, Snakes, Infected, etc.. I couldn't stop laughing for a good 30 mins, as they kept wailing about in broadcast, till they finally left back to blue. This is before Blueside ATs could go red, so they were trying play Red ATs, most them were Masterminds and couldn't figure that out, lol.
So yah, with current state of game, least on Excelsior. Folks are frigging lazy and wanna sit in an A,E. Farm all day. Listen, I understand wanting to get 50, but WTF you going do when you get there? Sure you can do all your lvl 50 contacts(Like I do for cash/Incarnate stuff). But once I'm done, I retire them. Move to next character that I work on.
So unless they make it so they can press a button to level up in a mish on Red Button, it's still going be low pop on that side. Even then that might be to much work for them.