There is a lot of that currently. Mancini, Ranieri have won the PL and Rodgers was within 3 games of it. What differentiates De Boer for me is that he has won it 4 seasons in a row, and has always finished in the top 2. That is a level of consistency over 6 years that is markedly different to you what we currently have and most of the managers above.
It should be noted as well that Jol had Ajax languishing when De Boer took over. The De Boer Ajax side far outdid anything Jol's side did. As for McLaren I do think he suited the Dutch league. He is known to be a fantastic coach and works well with young players which is largely what the Dutch league comes down too. He also did ok at Derby though terribly this season at Newcastle.
People are making out the Dutch league is like the Scottish league which is nonsense. Feyenoord, Ajax and PSV are leagues ahead of anything in the Scottish Premiership and the only team that would get close to them is Celtic. PSV are a very strong team and would are came closer to knocking Madrid out than either Bayern or Barca (lost on penalties) and also knocked United & CSKA out of the champions league. De Boer has been competitive with that size with a budget that is smaller than Everton's and a top signing of 4.5 million.
It would be a big risk as he'd only managed in Holland. I think De Boer would be a big success here and it's why Liverpool and Spurs have approached him in the past. He's needed to move on as for reasons people mention there is a limit of what you can do in the Dutch league. This is the guy who developed Blind, Vertnongen, Alderiweld, Eriksen giving them all their debuts. If he can do that here, without the same imperative to sell I think he will be a success.
Any manager is a risk. However the risks of De Boer his detractors are greatly over playing and simplifying. I think if we got him and some of his backroom staff he would turn us into winners quite quickly.