I really don't think so. There's a ton of reasons not to trade them:
1) If Rondo hadn't hurt his arm last season, there's a real argument to be made that the C's would've gone 7 games and maybe even beat Miami. From there, they really could've taken the Bulls and Mavs. While the team is a year older, with possible improvements from Rondo and Green (and JO for that matter, he's younger than Pierce), it's worth giving this group one last shot, particularly in a potentially shortened season.
2) Doc is back. That increases the odds of them staying.
3) But most importantly, the best value that Danny can likely get from KG and Ray is to simply let their contracts expire. I know there's this notion out there that Red should've traded the original Big Three. And maybe he should've; however, that doesn't apply here.
Everyone likes to talk about the merits of trading KG and Ray, but no one actually ever gives a viable, realistic scenario. Exactly who should Danny trade KG and/or Ray for?
Young teams won't have much interest in two aging superstars, and even if they were to want them for "leadership" they aren't going to give up young superstars for Ray and/or KG. Rather, they'd likely give us Jeff Green caliber players or worse (likely worse).
While that may not sound bad, we'd also have to take on Jeff Green caliber players either at KG's salary (20 million+) or Ray's (10 million). And it doesn't make sense to lock up that kind of money in that kind of player.
Veteran teams would probably be interested in them; however, they'd probably give up even less. And again, the problem becomes taking back the comparable salary.
Unfortunately, this isn't baseball where you can just trade your aging superstars for cheap young minor league talent to build up.
Thus, the best value Danny can probably get is to just let Ray and KG walk and clear 30 million dollars worth of cap room.