Lanefan
Victoria Rules
In total, yes; but the martial side and the caster side would each have to be weaker than their single-class counterparts such that the total of the two parts is roughly the same strength as the dedicated classes.No. As a class, it should not be weaker that either a dedicated martial or a dedicated spellcaster. It should be just as powerful, in and of itself, as either.
To clarify:
You have a pure Fighter. You have a pure Wizard. You have a third class that tries to be both a Fighter and a Wizard at the same time - call it Gish, call it Swordmage, call it whatever.
If this combination third class is as good a warrior as the pure Fighter AND-OR as good a caster as the pure Wizard, you've got a problem because now there's no reason whatsoever to play either the pure Fighter or the pure Wizard: this class completely overshadows one or both.
Thus, the third class has to be weaker at fighting than the pure Fighter AND weaker at casting than the pure Wizard such that when added together the two elements make up a class of about-equal strength to the 'pure' classes.