In terms of the site itself, I would want tu to be able to change your username. Some sites only allow tu to do it every 6 months after tu last changed it, so even if fanpop would just do that, I'd be a lot happier with the site. And if there was an app, that'd be awesome!
I would make the site a bit más similar to Facebook, create an app, give it connecting to other websites, I would allow nombre de usuario changings too.
The only thing I'd like to really see on fanpop is más trofeos and más opportunities for tu to get to talk with the admins of the site, like Dave and Cliff.