in roster construction? Been a few years, but I *thought* I saw that they found a few narrow little slices of player productivity which were impacted by adjacent talent on the same roster (I want to say baserunning was one of the set-in-stone examples of where having a guy like Ichiro elevates other players' baserunning productivity, but I don't remember where or even when I saw the work so take it with a lump or two of salt).
But this is one of those cases (intuition vs. statistics) where I think we have to demand the stats leave no room for the shadow of a doubt regarding the impact of, say, a Franchise QB's impact on a team. I think it's good to have pause, which is what my understanding of current stats analysis provides, when it comes to (possibly) overvaluing a Sandy Koufax, Randy Johnson, or Peyton Manning. But I also think that Things Are Done A Certain Way for *generally* very good reasons. In the NFL, if you got to re-draft every team every year from the available players, the first handful would always--always!--be the franchise QB's.
That ain't no coincidence, and it ain't a demonstration of blind dogmatic adherence to tradition.