I think new races would be cool, but when it comes to race in general I place higher priority on balancing the races already present as options.
As far as classes/subclasses go, I'm honestly surprised that Divine Soul Sorcerers aren't already in the game.
As far as I'm concerned, Divine Soul Sorcerer is the correct class/subclass for The Dark Urge.
I'd also like to see Death and Twilight Domains as cleric subclasses,
Because they both work as lore-friendly Shadowheart subclasses, though the second only works depending on your choice in act 2