Life Buildings

Actually, that's why there are two Life Mages – to quickly apply buffs to the Crusaders.
Regeneration allows you to avoid healing the Crusaders every time; you can regenerate, attack, and regenerate again, and the Crusaders won't even spend any health.

And I did forget about the Haven, but it's still only needed to remove retaliation with illusions; slowing down a single stack doesn't make much sense, and instead of general slowing, it's better to just create one stack.