I see the magi class as a basic utility class that has two dimensions. The first of those dimensions is a back up makeshift tank. The second is a limited scrappy wizard. The class structure as it stands now isn't bad. I mean it's a fair trade off to get both worlds of wizard/fighter but obtain those class features slowly and starts a little weak. The magi is a better option then mutilclassing fighter/wizard. The peak level in my opinion is level 12. At this point this class can get very potent. In fact I believe when the magi is built with the proper feats and right magus arcana this class exceeds the power scale to some degree. The reason I say this is because it's moderate possibility for the magi class at 12th level in one round cast three spells and have two attacks, three spells in one round. That is just nasty! I am very pleased at the creative nature of the class. My only real suggestion is to build in a few more options for magus arcana.