Bruschi didn't come into his own until he was moved to ILB in the 3-4.
This isn't the PAC-10. It's the NFL and it took Bruschi years to become a full-time player.
Sam would be a downgrade from Spikes, IMHO, even with Spikes already gone. I've not seen anything that shows that Sam has the ability to cover TEs or RBs. On the contrary. Everything screams that Sam would be a hinderance on the football field because of being slow and not having great agility.
The Pats are planning on playing Man-Man Coverge, not Zone Coverage. Bruschi excelled in Zone coverage.
Sorry, but I find it deplorable that you are comparing Sam to Bruschi when Sam hasn't shown Jack yet.
Just no.