Ehh, i dont agree....
I think most of the fun came from being silly - in a "serious" context.
Thats why i liked SR2 the most, it had a lot of humor, but it also had drama. The world seemed.... ugh, i hate to use that word, but for the lack of better - more "believable", than SR3. SR3 was so disconnected from realism, it was just a bit too much imho.
Then again, its a sandbox game. 80% of the fun comes from "endgame", like plowing with a tank through the streets, only this time, the tank has lasers. (btw. i think giving lasers to enemies was a bad move, because it made the matter even worse)
Im prob gonna get it anyway, i deal with a lot of juvenile bs in my everyday life, so seeing it on my PC screen doesnt affect me as much as it does others i think.....