It kinda goes like this:
Crappy app +first post thing = Mostly Bad votes= Rejection
Crappy App - first post thing = Almost all Bad Votes= Auto Reject
Good app + First post thing = Good starting votes= Testing.
Good app - First post thing = Mostly neutral votes= Testing or Rejection
Excellent long App - First post thing= Mostly Neutral Votes= Testing
Excellent long App + First post thing= Almost All Good Votes= Testing
The first post thing doesn't kill you most of the time but it is a deciding factor.
Voters: If the first post has not been read you should still vote with an honest opinion. not just shoot them in the head with a no because of 'first post'. if they look like they have what they need even without the first post then there is no need to deny them. If they look like they didnt spend even 5 mins on the app then feel free to No the hell out of them.