Considering most people's opinions on what the Artemis Fowl movie should be like I will probably be in the minority but I think making it "Epic" would be a mistake. I have always thought that the first book had such a focused plot that spending too much money or time setting up the characters and setting would be the most obvious mistake. What I have in mind, and hear me out on this, is to use as few sets as possible and only the most economic camera work, to give Fowl manor a claustrophobic feeling, and to write the script as a psychological thriller focusing mostly on the the mental state of Artemis and Holly. It would be so easy to do, considering Artemis' family life, and the mental status of his mother, it would make a good focus for his character since his emotions were exclusive to his inner thoughts which obviously wouldn't translate to film. Holly on the other hand would have the most room to work with, first is the downright mental torture Artemis commited in the first book, not only did he lie about how long she was captive but he also claimed he drugged and questioned her and that she was the one who revealed his knowledge of the LEP and the hostage fund. Another interesting theme to apply would be the deteriorating trust between Artemis and Butler over the safety of Juliet. After all one of my favorite scenes from the first book is when Artemis gives them the champagne and Butler takes the time to tell Juliet he loves her before asking Artemis if he has to drink it and the argument between him and Artemis immediately after they awake. Obviously Butler trusts Artemis with his life but not so much with Juliet, that is my opinion at least.
As for who should direct, if it were a psychological thriller like I invision in my mind than my top choice would probably be Nicholas Meyer.
"There will be consequences for this, he thought. You can't alter time and be unaffected. But whatever the consequences are, I will bear them, because the alternative is too terible."- TLC