Very difficult to compare rookie seasons even though they play the same position because there are both pretty unique players. The stats look pretty even and by my eye test, I would say pretty even in terms of what I expect of Smart going forward compared to what you would have expected from Rondo moving forward at that time.
Rondo had glaring weaknesses that he has never overcome (shooting mainly). Eventually, the league figured out how exploit that. Smart is still not a good shooter either, he still has plenty to prove.
The defense thing is a funny one. My eye test tells me that Smart is a better defender, by a meaningful margin. I know that Rondo has the All Defensive team accolades but I never thought Rondo was that good of a defender. Smart seems to have the ability like a shut down corner to take a player out of the game. I never saw that with Rondo. Rondo was always a very productive rebounder and I think that figures into the all-defense awards.
Rondo also has some all star years and I don't think it is likely that Smart will be an all star (maybe) but I don't think that means Smart won't be as good as Rondo. There were 5 or 6 excellent PGs in the west through those Rondo all star years but much weaker talent in the east. Antoine Walker was an all star too but I never thought of him in the same way I think of some other all stars. It is kind of the same for me with Rondo.
Bottom line, I like Smart and I think he will be better than Rondo.