2. According to SynergySports' stats Allen, Pietrus, and Pierce (via reduced minutes) got more points per possession in transition than their replacements Green, Lee, and Terry on roughly the same percentage of plays. Probably attributable to better 3 point shooting as "trailers" than anything else, but really a very small downgrade. IOW, if we get a lot more fast break scoring, it's going to be because of better rebounding, not better finishing by the wings. (Sullinger might help in that regard since he appears to be a good rebounder and passer, but how much time he'll get is a guess).
With the exception of Green's brief stint (which isn't worth counting) neither of those guys played on a team with Celtics defense and Rajon Rondo running the break.
Neither Kyle Lowry, a 2011 Russel Westbrook or a 40 year old Jason Kidd runs a fast break the way today's Rajon Rondo does...and neither the Rockets, the 2011 Thunder or the Mav's turn tough defense into quick offense the way Boston does with Rondo running the show.
Those numbers really aren't an accurate comparison. While Pietrus is capable on the break, neither Allen nor Pierce is really a 'fast break' type of player at this point in their careers. Allen is more inclinded to pull up for a three, and even Pierce doesn't really have the athleticism to keep up with Rondo.
Rondo, Bradley, Lee, Green and Wilcox may well be the best fast break lineup in the league. Rondo and Bradley are two of the best in the league at forcing turnovers, and when they do every guy in that lineup will be out and running.