The proper question in regards to Doc may be: Could anyone else coach this team as effectively?
In my opinion, Doc is the only coach for the Big 3 era. For better or worse, and admittedly we've seen a lot more 'better'.
My two biggest critiques of Doc are that he plays his starters too many minutes/ignores his younger guys and that his offense can be so predicated on perfection (ball movement, screens) that one small defensive wrinkle can make it stagnant.
However, could anyone else coach this team as effectively?
Doc's positive attributes are that he has the ears of his veterans and his youngsters (no small feat with the personalities he's had to coach), he never gives up and constantly inspires his team to 'keep grinding', he utilizes his players' strengths and attempts to hide their weaknesses (perfect example is Allen on offense and defense), and perhaps most importantly his players trust him and his system. Gaining the trust of his players is one of the toughest things for a coach to do.
Not many coaches in the league have as many positive attributes.
And, I don't think there is another coach out there that could have coached Rondo, Pierce, Garnett, Big Baby, House, Nate, Sheed, Shaq, and others over the course of a few seasons. Doc has handled quite a few personalities. He helped mold Pierce into the all-around great player that he is. He obviously shaped Rondo's career to date. He constantly pushes Garnett to be more aggressive offensively. He corralled the nutcases that are Big Baby, House, Nate, Sheed, and Shaq; utilizing their strengths while (mostly) hiding their weaknesses. Doc has managed to do a lot of good with what could have been a self-destructive locker room.
That is his greatest feat, in my opinion.