Ancelotti to Brazil has many pros and cons, many agree and many disagree and even regret his choice to coach Brazil, because for them Ancelotti is time to retire considering his old age. But in my opinion, every great football manager needs to coach a national team to prove that what matters is not only their tactics, but how well you can utilize the players available. You can't buy the best goalkeeper, defender or striker for a country. You have to utilize their strengths and their love for the country they represent.
I think only time will tell if this move is a good one and that's the same for Thomas Tuchel who is currently the head coach of the England team. His move to England was accepted by many and also questioned by many but we will soon see how this goes especially in their world cup performance next season which I think is among the main reason they signed them.