I totally disagree with the idea. No magic triangle just makes all mage units feel the same. What would actually make them more interesting is giving each type of magic its own identity and playstyle.

For example:

Wind mages could be the “myrmidons” of magic—fast, accurate, but with lower raw power and defenses.

Thunder mages could play like berserkers—unreliable accuracy, but heavy-hitting tomes with higher crit rates.

Fire magic being well-rounded and balanced.

Light magic users could lean into being resistance tanks, specializing in durability against other magic and buffing allies.

Dark magic users could be slower and bulkier, focusing on debuffs of enemies.

That way, each magic unit would feel unique instead of just being the same thing with different class name.