If this movie is going to work, He-Man better not be pacified, and the movie will need more than a G rating to be taken seriously by today's highly critical audience. He-Man has already existed in the 2-5 year old friendly world of Filmation, using his ridiculous strength to gently nullify blundering goons without as much leaving a bruise.
I am perfectly fine with the big barbarian going in, sword swinging and cleaving arms, or fatally slashing a ravenous lumbering beast to keep them at bey in an attempt to save Eternia. To think any less I feel is selfish and unfair. It is not a 1980's kids cartoon that will breath new life into this property. If that is what you want, stick with your DVDs.
I want to see He-Man get dirty, but without gratuitous violence. If you are a super strong barbarian with a sword, going up against monsters with claws, fangs, and knives, someone is going to get hurt. Most parents would agree that Spider-Man was very kid friendly, and even Spider-Man had bloodied sequences.