Edited by ZOS_Hadeostry on August 1, 2022 2:06AM
In the vampirism quest we are introduced to Lamae, the first Vampire who was turned unwillingly. As we learn about her past, we get specific lore that "her wounds healed on her own" and they therefore had to burn her after Molag Bal corrupted her. I can understand that they thought fire weakness was a thing, but Lamae stands up from the fire in the flashback, seemingly unscathed, and kills them all. This suggests that her regenerative powers outdid the damage the fire could cause, or that the fire did nothing. So either she actually has high regenerative power, or she is immune to fire- which is it? Given the vampirism skill line passive, this piece of lore is unimportant and a throwaway. At all stages, you have increased damage to fire, and decreased health recovery.
I won't even touch the ability cost aspect of things because that isn't addressed by the "lore" and therefore doesn't conflict- the devs can do what they want with it.
If this were not enough, we are encouraged by Lamae to feed on others to accelerate our gift- which in the end leads to zero health regeneration at all and more hit to our fire resists.
Neither the fire debuff nor health recovery debuff given are supported by the lore given to us by patient 0. Vampires are either immune to fire, or have rapid health acceleration (the latter makes sense given the lore), but they do not suffer debuffs from both if we are to believe the first flashback.