Late to this thread, but I'm somewhere between: I like this very much and I love this. Don't see how anyone sees this as a loss, regardless of further moves this off season. This strikes me as a win without qualification. Separately, I'm kind of puzzled what Presti is planning for that humongous pile of draft picks, but whatever:
(1) If you look at it as Kemba for Horford, and the #16 for Brown, we won on both it seems, though #16 for Brown might be a slight loss. People always like to prospect-hump on the draft, but most of those guys outside the top 10 don't pan out. I'd say #16 for Brown is a win for the Celtics, because they've already got too many young bodies fighting for time; they don't really need another rookie. Last year, if I recall the stat correctly, they were the least experienced team in the NBA (though not the youngest), at least early in the season.
(2) What'll we do at the #1, as others have noted, isn't as big a question mark as some people make it out to be, because Kemba was never a pure point guard. He was often hunting his own shot. His style was more that of an undersized #2. Smart can be a #1. I think Pritch is a really solid back-up point guard/occasional starter. I'm not as optimistic about Romeo turning into a #1, but they can experiment anyway. And they can run the offense through Horford sometimes.
(3) The team needed to get bigger, and this takes a large step in that direction. Horford gives them flexibility. Plus, this opens up the possibility of running out lineups pairing Time Lord at center and Al as power forward ... man, would love to see that. That may be a better role for Al, and would help preserve him from getting too banged up. Plus, if people remember well, Horford had some amazing games in his last year here when he started after about four days of rest. It was like night and day. With the glut of centers, that becomes more possible now.