I believe that Ancelotti will transform the team and bring out the best of them, because Brazil has great young players doing pretty good in their various clubs. I am happy that the Brazilian National team will be lively again.
Since Ancelotti never succeed with a national team, I'm not really sure that Ancelotti can instantly improve the performance of Brazilian team. But I believe Ancelotti has the ability to change Brazilian team, he has proven his ability by winning varied titles. Ancelotti is also very familiar with many Brazilian players. So, it will make it a bit easier to rebuild the team.
Ancelotti main task in the Brazilian national team is not easy, he must rebuild the squad which was considered incapable of competing at the international level since it was still handled by Dorival Junior. Ancelotti has the ability to transform the Brazilian squad into a stronger one, but it will take him a long time to bring Brazil back to winning trophies.
As a coach who has won five of Europe's top leagues, of course he has no trouble with the Brazilian national team because they have quality players spread across several top European leagues. Argentina is still Brazil's nightmare because they are still able to maintain their best performance after successfully winning the World Cup trophy.