Not only was Rose's ACL tear far more extreme than Rondo's, I'm not sure what your point is that Rose's ACL injury screwed him. Do you have a crystal ball that tells you that when Rose returns, he's going to be a shell of his former self?
Baron Davis tore his ACL in college and went on to have a fine NBA career. Jamal Crawford, too. Both of them are guards who relied on quickness and explosiveness. Both of them also tore their ACLs over a decade ago. Medicine and rehab has gone a long way in the past decade. More recently, Al Jefferson, David West, and Ricky Rubio are guys who tore their ACL but returned just fine, if not even better. Do I even need to mention Adrian Peterson?
Considering Rondo's work ethic and drive, I hardly doubt he messes around with his rehab. The chance he comes back as a worse player is much less than you think.