There's no question that losing Garnett - if he actually is lost for the season - is the bigger loss. Garnett is the defensive anchor of the Celtics, and without that, they're in trouble - most especially when they face teams with strong power forwards. Fortunately for Boston, those teams are mostly in the West. But this is a big loss for them.
As for Dallas - don't sleep on this team. Offensively, they've got weapons; defensively, they're playing for a new coach with a new style; and if Brandon Bass steps up his game, they've got the ability to go big with Kidd-Howard-Bass-Nowtizki-Dampier or small with (Barea-Terry-Kidd-Howard)(pick 3)-Bass-Nowitzki. Carlisle is a playoff-tested coach. And this is a team with a chip on its shoulder. They've got guys with playoff experience. And if they don't pull it together post haste, they'll find themselves distributed to outer darkness while Cuban tries to rebuild a winner. Pressure's on; it's put-up or shut-up time for this team.