Yes, the starting 5 are old on average. But as long as D12's back holds up his presence negates a lot of that aging. He can cover other people's defensive mistakes and get out on the break like a bullet -- something Bynum could never do. Throw in Hill in the post and we got younger and more agile inside.
And if I need to remind you, youth isn't everything. We don't need a team full of high-flying young guns who are dunking one minute and throwing the ball out of bounds the next five. We need solid, steady play, aiming for the kind of grind-it-out basketball that tends to win come playoff time. (Yeah, I know -- OKC and Miami play small ball. Well, I don't think small ball is here to stay.)
As for how sucky the bench is, we don't know. Jamison and Meeks are both new this year and still settling in. And the holdovers haven't seen a lot of playing time. As far as I can tell, our three point shooting is already better than it was all of last year, and that's been one of our most pressing needs.
In any case, I'm not saying people aren't asking valid questions or pointing out obvious deficits. But the answer isn't to freak out now and change course or throw up your hands, it's to be patient and see how things evolve.