With Mason's system, they would've won 5 games ... subjective for sure, and I'll admit this, way better chance of 4 wins than 6 wins ... but when you lose 7 games by 7 points or less, I think Mason's system would've overcome some of those tiny deficits.
Familiarity would have likely breeded a couple/few extra wins, yes that is not hard to guess. But how many transitions have you seen where a new coach comes in with a different system and is able to max out the talent he is handed on his squad. Michigan is a pure example of that. 10 wins, a win over Florida, I think most would have said they had "7 win" type talent at least. They won 3 games. They won 5 this year even. This is Michigan of all schools. Coaching changes are tough on programs, and usually involve a step back when the new coach gets there, unless that school already is at the bottom when he is hired. Mason leaving "5 win" talent means with a coaching change, 1 or 2 wins is far from shocking with ANY coach, let alone one with no experience like Brewster.