7 Superbowls can be "A" reason that you argue in Brady's favor, but it can not be "THE" reason you argue his greatness. Superbowl victories are a team accomplishment. More often than not, the better team wins the superbowl (often times in spite of the quarterback's performance).
If you're going to count all the playoff victories and superbowl wins as an individual achievement, then you should factor in the quarterback's contribution to those victories. If you do that and look at the numbers, you'll quickly find that Brady's quarterback rating in the playoffs was worse than his regular season rating (which has always been used as a knock against Peyton). You'll find that Brady in the playoffs (thought of as Mr. Clutch in the playoffs) is only 3 QBR points ahead of Peyton in the playoffs (reputation for being a choke artist in the playoffs). If you look at Joe Montana's average QBR in the playoffs, it was actually HIGHER than his regular season QBR. And his playoff QBR is TWENTY points higher than Brady. Montana's contributions to his playoff victories are greater and more impactful than were Brady's.
Summary, 7 SBs can't be the only criteria you judge by. Don't shout "SEVEN SUPERBOWLS" and then flip the card table over and walk out thinking you won.