As it stands right now, I agree with the OP, and things should only improve for Boston once JO, Perk and Delonte return.
I live in Los Angeles County and work at an L.A.-area newspaper -- in the sports department, no less -- so I get to see a lot of Fakers games on TV at work. They're definitely hurting on the big-man front, Kobe's lost maybe a half step, and if health isn't an issue, the C's have a better, deeper bench, but I still expect L.A. to be in the Finals this season. The Mavs are rolling but have never gone deep in the playoffs (though Tyson Chandler could help them go further this year), and the Spurs, though they have been to the promised land, seem unlikely (to me) to go a whole season without a major injury to Parker and Ginobili, and if either of those two go down, the Spurs' chances go with them.