I also play on deity, and i can confirm spawning next to two orcish goblin forts is VERY difficult, and luck-based, even with the 100% defense boost.
It also indeed makes early wiping of AIs under raging barbarians a non-factor, which is really nice and was a problem in vanilla FFH, in my experience.
In an actual war, it doesn't change anything, the winning side WILL win, unless a third party gets involved.
EDIT : Does Manhunter works properly ?
I'm getting slaves very, very rarely with Manhunter V...
It feels not like 50% chance, but 5% or even less. One slave every hundred fight or so.
Note that i am not running the slavery civic, so maybe that's related.
Speaking of order of magnitude, the global enchantment Fertile Lands does not works as advertised, it does double the base chance, but each nature mana adds 2%, not 20%.
Also, this one isn't really a bug or anything like that, but...
Is there a possibility to add a dummy promotion that gets deleted after purchasing it ?
My main huntress have 3000+ experience*, and i am resorting to periodically remove dozens of promotions to keep levelling her up. ( for bard culture gain ! )
Maybe a promotion that gives a special ability : the ability to remove the promotion..?
*Hidden nationality+blood blade+blitz+mage parked in range with experience aura makes it really easy to achieve ! A great commander too, if you're lucky unlike me.