Ideas and suggestions.

I want to reiterate my opinion about the Red Ball and the Cloak of Disavowal. Just two artifacts can ruin the Mage class, which would either require excluding it (and then a lot of changes would be needed for balance to protect against magic) or changing their properties to "Protects your troops from damage from enemy spells" (but not from your own mass Armageddon spells, etc.) for the Red Ball, and "Protects against negative effects from the enemy" for the Cloak of Disavowal.