No to Big Al unless we can get Dwight Howard/Marc Gasol/Joakim Noah to play D.
There are good defensive bigs outside of the top 5 centers in the league. Okafor, Dalembert, and Hickson all come to mind and are all UFAs this offseason.
I'd take Rondo-Bradley-Green-Jefferson-Okafor (+Sullinger) any day.
No to Josh Smith unless he comes for Jeff Green money.
That won't happen, and it shouldn't. Smith is a better player than Green. Better rebounder, better defender, bigger, stronger, and more capable of exploding for 10 straight points.
Smith is a top 20 player in the league. I'd call Green top 50.