We use relegation within our league (12 team FG H2H). We use 3 divisions: Gold, Silver, Bronze. Last place in the top two divisions is relegated and the first place in the bottom two are promoted. Fun way to keep folks interested and keeps the competitive balance alive, as the division winners get auto berths to the playoffs.
I’m not sure if the takeover system that you’re describing appeals to me, personally. Mostly I’d fear that it could be a race to the bottom for a mediocre team, if they just get to take over a winner the next year. I can see marginally more interest in taking over a last place team in an upper league (some people enjoy the project). But, assuming the upper level are really talented owners, a quick rebuild (as Braveheart mentioned) is a tall order that might have limited appeal as well.