I tested this myself too.
9 games in I simmed to the end of the season and the league averaged just under 6.6 SO per team per game.
6 players finished with over 200 K's.
3 teams hit over .270.
These were easily, far and away, the best results I have seen to date.
So to answer the question, I agree with the quoted above. You do not have to restart your current Franchises to see the benefits of the new patch.