For me, at least, Shep had the "Let's explore the galaxy and make friends, never giving up hope in humanity." part of his brain at least partially removed and replaced with the "Whoa, those female soldiers are hot (*drools*), I'm gonna follow them. Duuuh, Laryn's hot. Did she ask about me?" part. He came across as immature sometimes. He also seemed to be in some kind of a "funk" that made him kind of short with people (or nasty) during the last 2 seasons compared to his behavior in seasons 1-3. He just wasn't 100% of the Shep I got used to during the first 3 years of the show, and I liked that Sheppard better.
"Survival is the only mission", eh? "Making the most of our entitlement to act like spoiled children is the only mission" is more like it.
Yes. And the only "experimenting" that's done should live and then quickly die with SGU. I don't want them to experiment with the personalities of Sheppard, O'Neill, Rodney, or anyone else from Atlantis or SG-1. Leave their personalities in-tact, please. Creative paws off! These characters do not need to be reinvented. TPTB need to remember this. If they can manage to remember this (and these characters' back-stories), then I think Extinction and Revolution will turn out nicely. Anything else would be fan abuse. And, the wasted hours of my life spent suffering through SGU before finally giving up was abuse enough for me.