Not a fan of the play-offs - in my view a team that finishes 3rd and 4 points clear of the next team over 46 games should go up. If you have to have play-offs I like the current German model - bottom two in the Bundesliga go down, top two in Bundesliga 2 go up. The final relegation/promotion place is a play-off between the third bottom in the Bundesliga and third place in Bundesliga 2.