I loike the new header, it's bold and bright, the other one was nice, but felt like it was trying too hard and ended up a bit too busy. This one seems more polished overall.
However, I do agree on the slogan, I don't see what the big problem is with the old one, it was catchy, and it is one of the things that makes this web-site. To me the phrase "The problems of the future, today!" always implied a freedom of expression that other sites and outlets never truly allowed. This site was happy to be controversial and allow such content (hopefully most of us remember the teletubbies paradies and the BBC complaints, if not then go look!)
Everything, by everyone, just doesn't have a ring to it really. It doesn't even make much sense to be honest, as it's a minority of people who have actually made things for this site, hardly 'everyone'.