Some very good posts here (and a selection of LetsRun misguided/trolls as well). 27:36 in Beijing, running a lot solo when Bekele was busting his ass to run ~27-flat tells us something. I think that Rupp is probably at least half a level better this year, although he was peaking last year for one key event while he will not have that structure this year.
I think that he will get the AR whenever he races in good conditions at peak conditions (possibly the WC's but all sorts of things might derail those possibilities, from championship race pacing/irregularity to having to have so many peaks). I think that Nelson is being overlooked and might give Rupp a run for his money to an AR (which might really make a fast race under the right circumstances, but I do not think that they will run balls-out at USATF because it is a top-3 race not a winner-take-all objective).
I think that American distance running is returning to a level that marked the first running boom, although it is not there yet. [look at the stars we have now: Lagat, Teg, Rupp, Solinksy, Hall, Ritzenhein, Fam, Webb, Manzano, Lukezic, Lomong, Nelsons (Tim 10,000, Billy SC) Symmonds, Wheating, Fernandez, ; Barringer, Willard, Goucher, Kastor, Shalane Flanagan, Rowbury, Wurth-Thomas,...; I have left out a few and focused a little more on the younger ones than the older ones without even listing 9:40 college SCers]