Good points, BCelts.
I guess it really comes down to how Ainge feels about contract renegotiations with Rondo and Ray. If he thinks he can get both for about $20-22 mil a year, I think he does it. I'm not sure having a big contract on Rondo really saddles you anytime. He's shown he can be a good point guard and help great talent emerge, which is a desirable quality to prospective free agents. As long as we don't give out a bunch of big contracts to undeserving players post-KG/Pierce/Ray, then we won't be stuck in purgatory.
If Rondo wants more than a 5-year, $60 million deal, I'd definitely look to deal him. I think $10-12 million is good compensation for him, especially with long term security. As for Ray, I think $7-9 for three years is a fair deal since I think he's got one to two years of starting left followed by a year where he's best served as a sixth man. But if they're not willing to take that kind of money, then I see why Ainge is thinking about a trade that helps us now and opens up more potential future flexibility.
Of course, if we were to trade him for CP3, it wouldn't be cost-saving, but cost-incurring.