At early levels you can only cast a spell class three or four times before he has to rest at an inn, so you have no choice but to use his very weak physical attack. On top of that, Fire and Lit spells are in the same class. You won't even make it past the first floor of a dungeon before getting in three random encounters. It's better to have a stronger class that can 1-shot one of whatever you're fighting. At later levels it's better to have the WW use the spell items like Thor's Hammer and the Mage Staff since there's plenty of downtime between healing, again freeing up the slot for a class that can 1-shot what you're fighting. There's no point in the game where you have an advantage by using a BW, since bosses have a very high natural resistance to magic like Nuke. I would even take a TH over a BM, with their only advantage being able to run better, and the only thing in this game worth running from is a group of Sorcerers.