It's a really good question.
For me who has been around for Royle, Kendall (2), Smith, Moyes, Martinez, Koeman, Allardyce, Silva and now Ancelotti, Martinez's first season was by far my most enjoyable year in terms of the way we played.
I disagree totally with
@Groucho regarding our defending (or the suggestion we didn't do any) in that first season. Our defensive record overall was very good with McCarthy especially absolutely fantastic in winning the ball for us.
But as I've aged, I do appreciate more that there are plenty of ways to skin a cat. Take Ferguson taking over and going 442. The idea of having two strikers in tandem has ended up in practice working very well for us. With absolute love and affection for Dunc, I don't think there was much longevity with how we were playing in the 442 under him. Vs Arsenal, tired of course, we lacked any real attacking impetus.
What was fantastic though was to show how Everton should be intense without the ball. That McCarthy bite in the midfield, pressing forwards and physically dominant CBs are an absolute must for any Everton side.
Conversely though, what I don't like sitting on the Gwladys (for my sins), is the absolute impatience and annoyance of some to just "GET IT UP THERE". However we play needs to be with method and understanding.
I have absolute trust in Carlo to find the way that best suits the club to progress.