I think Philly has some pieces with nice potential in Noel, Embiid and Saric but none of them have played a game yet. MCW is ok as your starting PG but I think they'd have been better off trading him to Orlando and keeping Payton. I was under the impression that Bennett was going to Minny in the deal, not Philly so I wouldn't include him as a Philly asset just yet.
C's have more young players that have shown they're NBA-caliber players in AB, Sully, KO and solid prospects in Smart and Young.
C's have more picks to both use for young talent and for trades. C's also have better players available on the roster for trades than Philly and that's by a significant margin. Philly has Thad and that's it. C's have Green, Bass, Thornton and Turner who could all be moved to a contender for more assets.
The C's also have 3 non-guaranteed contracts to use in a deal for another good player or more assets.
C's also have the best player on either roster in Rondo.
Both are headed for the lottery this year barring a real shock. Overall, I think Philly's youth has a higher potential than what Boston has but Boston has far more assets at their disposal to accelerate their rebuild so I'll give the nod to Boston at the moment.