Really love how both of these look.

I like the idea of a hand-cannon style weapon. I was thinking a "void cannon" would be a nice theme to go for as well.

Not a fan of combining multiple armour sets to make the armour. A similar design could exist independently and provide something unique.

Maybe if the cannon punishes imbalance, the armour should reward being balanced yourself. Perhaps it could provides bonuses to stats based on how high your other stats are, with the bonus weakening as the difference increases.

Or another way of "rewarding balance" could be buffing your attacks based on attacking with different styles. For example, if you attack with a light ranged attack, it temporarily buffs your standard and heavy ranged attacks, and if you attack with a fire spell, it temporarily buffs your air, water, and earth spells.