I think you greatly underestimate the attendance boost.
In my div3, a classical promotee who delegated made 500k more than I did over the season and I promoted the new way (was also in the finals so your way would've worked for me too) and more than that, he wasn't paying attention to his prices while I kept trying hard (I even made the playoffs...)
So the attendance bonus is a huge must have in my opinion, I would've rather stayed one more season in D4, I might've made more money there
But I get your point, the playoffs should not be friendly games !