The main rule of the TES series was "Be who you want and do what you want".
And in the series, you can always make a hybrid build, but for some reason in TESO you can only make a hybrid based on stamina and weapon damage.
But even if you decide to make a hybrid based on magic and in medium armor, through the "Pelinal's Aptitude" set, you will face such a problem that you will not have suitable potions for hybrids, because they always refer to either mana or stamina.
Suggestion: enter an ingredient that will allow you to create a potion with effects:
major prophecy
restore magicka
major brutality
To do this, add an ingredient with effects
restore magicka and major brutality.
This will give the opportunity to create hybrid builds based on mana.
@ZOS_GinaBruno
Theorycrafter manaNB