[rossitter]

This wouldn't really be pro/rel, not as it's implemented in European football anyway. It's a single league where entry into the lucrative year-end tournament is partly based on long-term (3- or 5-year) performance, whereas now it is only short-term (1-year).

[xphilter]

So pro/rel. I think Mexico’s soccer league has a multi year relegation system like this already.