Absolutely agree with the title.
Bradley is bar-none, the best on ball defender in the NBA. He was shooting over 50% from 3 as a starter and over 50% from the field. He showed lightning quick agility and ability to get to the rim on his own, the ability to hit a step back jumper consistently, and was great off the ball and in transition with Rondo. The kid has a shaky handle, but he's only like 21.
Bradley was a beast on defense and showed a lot of talent and promise on the offensive end.
More than that, he's shown he "gets it'. Doing all the dirty work, never complaining about role, always doing what's best for the team, playing through pain for the team. He's a blue collar Celtics who prides himself in being able to do the dirty work.
Bradley does not leave unless it's for a big time superstar in a steal of a deal. I would almost go as far to say as he's untouchable unless it's for a top 10 player.