Being almost 52, I would like to think that decades of experience are valuable, and I also think I can usually tell pretty quickly after picking up a paper which ones are put together by grown-ups. Unfortunately, from a business standpoint, it seems that all large papers are struggling pretty much equally regardless of whether they whacked by seniority or by inverse seniority. All that indicates to me is that newsrooms have less to do with readers' choices than we would like to admit.
Looking at it strictly from what a professional would notice in reading a newspaper, I think it's helpful to have a large number of people who grew up in the paper's home base, no matter their age. I've been the out-of-towner, and I don't discount the value of going out and grabbing the best talent you can get, and I even think a certain amount of turnover is healthy (Exhibit A: The Miami Herald in its prime). But if you don't have a large number of people who know a place in their gut -- and are in positions to make some decisions -- you are not only going to embarrass yourselves pretty often, you are going to put out a product whose general personality is generic. On the other hand, the worst top editor I've worked lived her entire life in that city, except for going to college two counties away, and the second-worst grew up close enough in the next state that he should know better.