True, trading Arroyo for Wily Mo Pena was a bad deal, and though it was the right move at the time, the Eric Gagne trade with Texas just didn't work out well (even though the Sox still won with him in '07). And even more true, Ben Cherington and Jed Hoyer traded for Josh Beckett and Mike Lowell during the three months in late 2005 that they were co-General Managers of the Red Sox when Epstein had briefly resigned. And though the Carl Crawford deal looks bad now, few quarreled with it before the 2011 season started, and he can only do better going forward.
On the other hand, Epstein did bring Adrian Gonzalez to town via a big trade with San Diego last year. The Sox may now be without its top pitching prospect Casey Kelly because of that trade, but Epstein has left a good farm system behind, though not as great as it once was. Otherwise, he and Francona would've had much better options than to have the Kyle Weilands of the world pitch important games in a playoff run as was the case during the "September Collapse."
But the good free agency signings, draft picks and key trades Theo Epstein made outweigh the bad in my view. And of course, his front office team (including Cherington) got Boston two titles it hadn't seen since 1918. Thus, even though his teams haven't done well the last three years, Theo Epstein will eventually go down as one of the greatest GMs in Red Sox history (and not just a "good" GM, as ex-Red Sox utility great Lou Merloni said this morning on sports talk station WEEI).
Now Cherington, who has been with the Red Sox since the Dan Duquette era (when he was a just a lowly intern in 1997 in his early 20s), has some big shoes to fill as Epstein's successor. He has his work cut out for him, starting with finding a new manager. And with that, I wish him good luck. He's gonna need it.