If you forget for a second the Ratliff part of the deal (which is huge, but bear with me), I still look at the draft as this:
Would you do:
Roy for Rondo
and
take Telfair at 22 (where Rondo went).
That's not nearly as bad as just looking at Telfair for Roy. Not bad at all.
I don't think you can look at it like that. Wouldn't people say, which would you prefer, Roy and Rondo, or Rondo and Telfair? I mean, that's the choice Danny had, presumably. Or, if he was hell bent on taking Rondo at #7, the choice would have been Rondo + 2007 draft pick (Rudy Fernandez), vs. Telfair + Rondo.
If this trade is just evaluated in terms of talent, it was a loss for Boston, no matter how it's looked at. If it's considered as a move for financial and trading flexibility, though, it's probably even.