Cat's pajamas, albeit I do think that Machaka's "Yasini the King Triumphant" should be left at H4, not H5. I think all the other heroic priests are simply one level higher than the normal priestly maximum for their nations, leaving Pythium and Marignon as the only ones who get an H5 for their utmost priest-hero.
Looked through them all just now, and it really makes them look like you'd be happy to get any of them - previously _way_ too many were imperceptively better than normally recruitabale units. (Example : Vanheim's Farbaut the berserker - dies just like that when the unmodded one is used in combat, even if you trick him out with magic items, at which point he _still_ dies and you lose the items.
)