I don't think the league has very strong grounds to do anything, unless someone confesses. For one thing, did they check the Colts' balls? What if they were all underinflated as well? Without those balls as a control, it will be hard to prove the Pats did anything. Is there any visual evidence? Apparently not.
I am guessing what happened here is that Brady let the equipment guy know he liked a slack ball. Equipment guy told ball boy. Ball boy sees weather is terrible and seizes his opportunity to help the team.
OTOH, Belichcik is not known as a guy who leaves things to chance. No one knows Brady as well as he does. Maybe he arranges it. Try proving that.
Ccomparisons to the Saints pay for injury scandal are ridiculous and prove that guys like Troy Aikman should stick to analyzing things they can understand. There was solid evidence of what the Saints were doing, plus they had a sordid history of cheap shots on QBs. Compared to Drew Brees, who actually defended his defensive players trying to injure opposing QBs, Tom Brady is a class act.
Brady is not the only QB who likes a slack ball and the league has no way of knowing how many other teams let some air out. It just shows what morons are running the league that they let teams control game balls.