IMHO Werewolf would fit the most as a Hunter, being more quick-attacking; even though it self heals, this isn’t necessarily a mage-exclusive thing (Mages and warriors both already have healers anyways).
Monk would do better as a Mage subclass since Monks in fiction/fantasy often mix magic into their attacks.
Brawler fits with warrior for obvious reasons.
Although, I personally would rather see the whole Martial Artist as its own class, as I feel that, with 4 classes and 3 subclasses each, we could see more diversity in the mid-game (levels 10-30 as players haven’t unlocked subclasses yet) since there are 4 different classes rather than 3. Plus, changing from Mage, Warrior or Hunter to a Martial Artist subclass would probably not work well with Stats and Skills.
Stats would work differently with these classes, more than likely, since weapons won’t be used. Same with skills; all the Warrior, Mage, and Hunter skills become obsolete as players choosing these subclasses no longer use the same types of weapons.