Magic stats are more important than you think. Any form of enchantment on your weapon or enchanted weapons themselves rely on your Magic stat and a Mystic Knight relies on enchantments & spells to deal damage (himself) since the rest of his moveset belongs to the more defensive Fighter class.

Generally, both Magick Archer and Mystic Knight differ very little from Strider and Fighter respectively when their magic stats are neglected.

Same goes with Assassin who is more like a dull combination of Strider & Fighter if you neglect his nighttime and poison abilities.