espn's John Carroll gave what i think is the perfect analysis of the Celtics main issue this year ......
"It is extremely hard to coach defense in the NBA and sustain it. When players hear the same voices year after year, it can get old, and it becomes harder and harder to keep them focused. Defense is not like a faucet -- you can't turn it on when you need it. Defense is a mind-set that must be instilled in a team every day. Two seasons ago, the C's had that mind-set. You see that from this Boston team only sporadically. The scary thing about defense is that once it goes, it is almost impossible to get back. There is no magic potion. The Celtics must commit themselves to becoming a great defensive team again; otherwise, they will be doomed in the playoffs."
age and injuries have contributed to this problem greatly - the Celtics 2008 style is so difficult to maintain over many seasons. they were the ultimate grinders and had to work very hard to be effective. when that style is working and in sync, it is a beautiful thing to watch, especially for basketball purists.
even in '08, i always said these Celts were kinda hard to watch on offense - but my God, they were a thing of beauty on defense, absolutely textbook team man-to-man defense. any attack to the basket was met with strong individual resistance and even stronger help rotation where every pass by the offense to take advantage of that rotation was perfectly met by yet another Celtic in just the right spot.
but this team has never scored a lot of easy baskets, the way the 60's and 80's groups did - this bunch is more the style of the 70's Celtics, though even Cowens & Co. scored easier with their running game.