He has the man management skills (players like him), but he lacks the personality to get that extra 10% to win the league. To win a competition, you need to have a manager who has the personality to inspire you when you are running on fumes at the end of the season. SAF, Mourinho, Guardiola, Simeone, Zidane, etc2 are not just managers but they are big personalities whether you like them or not. Ole doesn't have this (at least publicly he does not come across like he does), he is just a very nice guy who is half decent as a manager. Tactically I also think he is behind the likes of Klopp, Guardiola, Jose and some of the modern coaches from mainland Europe. Not far off, but still a bit behind. SAF was good tactically but he was not the best - his personality and man management more than made up for it though, and in his time it was enough to carry his teams over the line. You would never imagine us winning a game against a top 4 team now with a midfield of Oshea, Gibson, Rafael and Fletch. The game has moved on and I think he knew that at the end of his career and decided to retire whilst at the top.
For reasons of a lack of personality and slightly behind tactically, I think he will get us close but not close enough to win the league again. Would be extremely happy to be proven wrong as I do like him as a person.