If I may draw an analogy with a imaginary modern military class-based game, I want all PCs to first be distinguished from commoners as soldiers are from civilians. Then you have a Fighter class with an assault rifle and a handgun, and a Wizard class with some grenades and a handgun. When they run out of grenades, they use their handgun. That establishes some sort of basic connection with the Fighter class that I find pleasing. I don't like the idea of a Wizard class that, when they run out of hand grenades, they start flicking little pea-sized grenades that appear to have a very similar if not identical effect to the handgun. And they have grenades on their uniform and their helmet is in the shape of a grenade, etc. That plays up the superficial aspect of their class flavor too much. It's goofy.