I share a lot of your observations. I feel that Ridley Scott is not really required to direct this one. Ridley is more of a doom-n-gloom guy, look at Alien, Blade Runner & Gladiator. Martian is very light-hearted, too polite, very, very careful not to offend anyone, to the point of ...but it is rare to see a movie so sunshine-y and optimistic. I will be surprised if the audience at large does not embrace this one. This could be the Holiday Smash everybody is waiting for.
But here is the strange thing: this is probably the first film that I saw this year where the characters seldom argue, everybody's emotion is muted, everybody almost agrees on everything, everybody is gung-ho, everybody is teaming up, there is almost no crisis. The only character who is really frustrated is Matt Damon. And oh yeah, they didn't kill Sean Bean.