Ancelotti has been criticized for his training in the past, so it's no secret. He has also been criticized for his tactical stubbornness, and lack of creativity. But even if he has been criticized for it, that does not mean it is true.
Personally, I think the periods of good play have been too few under Ancelotti, but this can turn around, and the sample size is too small to assess him. However, we should be aware of this criticism, he is not above criticism, and one does not win matches on previous triumphs. Imagine today's team against Leeds, they would have been slaughtered.