a. By rushing for 900+ yards, which Rattay did not do...
b. As you said, by taking his team to the NFC championship game.
On top of that it's impossible to fairly compare the two because, though Vick played 6 more games, he still had 4 fewer pass attempts. Vick's stats were always somewhat skewed because of how often he ran.
If you don't want Vick that's fine. But don't act like it's because you don't think he is good. I agree he wasn't the best passer, Roddy White proves that. But the Falcons were always competitive while he was there and if you don't think the 49ers would be better with him than what they have... Then you're just crazy.
But I doubt they would grab him. And I also doubt he comes back anytime soon. So this doesn't matter.