Zlatan only scored 13 goals max at Ajax. Goalscoring statistics are a poor measure for ability. If that's all you're looking at you'll end up with players like Kezman, Ruiz, Altidore, Alves, etc. Other than that, 10 goals and 3 assists in 12 starts is pretty good for a 19 year old that just made his debut a few months ago.
As far as his skills go, he's got it all. He's fast, strong, intelligent, creative, technically exquisite, hard and accurate shot, goalscoring instinct, good in 1-on-1, strong link up play and a good header.
There are a couple of reasons why I don't think the move is likely. 1) Just last week he expressed his desire to stay at least a couple of years. He wants to be sure of playing time. 2) He has a contract till 2021. 3) Ajax just sold Milik for 34 million and are the most financially healthy club in Europe. 4) Every big club in Europe follows him and has been linked with him.
So unless Everton are willing to go absolutely crazy on both transfer fee and salary I don't see it happening.