You have got to have more than one great playoff game to make the HOF. I know Warner has had some great playoff games before this one but your argument for having one great game doesn't hold up. If that were the case Doug Williams and Timmy Smith would be in the HOF based on one great Super Bowl game.
QB's like Brett Favre, Tom Brady, and Peyton Manning are HOF quarterbacks. Kurt Warner, not sure about that. Warner has had some unbelievable games, some of the best of all time, especially in the playoffs, but from 2002 through 2007 he spent a lot of time as the 2nd string QB. HOF QB's don't spend time as backups like he has.
His three year run from 99 through 01 might be the best of all time but to make the HOF you have to do it for many years, and he just hasn't done that. If there were a HOF for playoff games he might make that because he has been great in the playoffs but over the long haul his stats just don't hold up.
I think Kurt Warner is a great QB, but he's just not HOF material.