Personally, I feel the relegation playoffs are too bloated. I realize Holland wants to keep as many clubs motivated for as long as possible, but 10 clubs fighting for 2 spots is a little ridiculous. I feel it is wrong for 2nd and 3rd place finishers in the Eerste Divise to have to re-qualify for the Eredivise by playing clubs that finished 4-7 spots below them in the table. The season should mean something; therefore, I think the Eredivise should change its relegation playoffs, either to the Bundesliga model (16th in Eredivise vs. 3rd in Eerste Divise) or the English model (3rd - 6th in Eerste Divise play in four team playoff for one spot). Also, this line of thinking also applies to the Europa League playoffs. The team that finishes fourth shouldn't have to compete with teams that finished below it. On top of that, the Dutch coefficient (which is currently taking a beating) would do well by guaranteeing the 4th place finisher is one of the Europa League entrants.
In the Jupiler league there are reserve teams of PSV, Ajax and FC Twente. The nature of these teams is that they are not all the time of the competition of the same strength, because of rotating players from the first team. So in fact they are a competition corrupting entity in the Jupiler league. It wasnot intended, but the way the play off is set up makes up for the corrupted results against the reserve teams.
I don't really care about the relegation play offs. But the play offs for European football are ridiculous and damaging to the league.
IIRC the reason for the inclusion of the three reserve teams was that the there were not any other clubs that wanted to move up to the Jupiter League because of the financial regulations. I agree this is not optimal but it is what it is.