http://www.cbssports.com/nba/stats/dunk-o-meterHonestly I don't think their dunk count is a huge problem but I think it reveals the underlying problem. Look at that list and you'll see most of the top teams in the league have a few entries high on this list. Heat have 2, Clippers have 3, Thunder have 3, Knicks have 1 (but at #3 overall).
The Celtics problems are simple. They have no inside presence, which results in what I call "jumpshot roulette" (works better in the playoffs) and plenty of easy layups on defense.
KG is still great but he's declining and can't do everything. Pierce plays like an old man (although a crafty one). Bass got paid and has sucked this year. Sullinger is nice but most NBA bigs can torch his D. Jeff Green is Charmin Soft™.
The Celtics need a big. I really think it's that simple. I think Fab Melo could even help. Let's all hope Danny does something about it.