De Boer
had 5 great years at Ajax, celebrating 4 titles in a row. Responsible for the development of likes like Kishna (not so great), Milik, Blind, Siem De Jong, Bazoer, El Ghazi, Cillessen, Eriksen, Alderweireld, Vertonghen, Anita, Van der Wiel. Dutch style of football meaning a lot of possession and control over the game. De Boer has a tactical brain though. His victories over Barcelona & City are among those games who could mean something tactically.
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Can develop youth
Doesn't require big transfers
He can work with a team that's losing major assets each year
Experienced in defensive plays
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Not experiences as coach outside Ajax
Ajax had the biggest budget in the league, so naturally he shouldn't have had much competition at all
New competition also means a new tactical plan, he played 4-3-3 most times
Anyway my opinion is that we should take the risk, but take it now then. Not 4 games in the competition.
Bielsa seems a indecisive turd and I believe we can kiss dealing with Lazio for a long time goodbye. (positive : no candreva or 30+, negative : no Anderson or Keita

) However, Bielsa is a great coach. With the right players he can work magic.
Villas Boas, hmm well. I wouldn't say no. He has interesting ways, but his latest jobs weren't great successes. Still better than Mancio.
Prandelli, he does know the Italian league, knows the ways, wouldn't require much. But I don't know about him.