TES vampires don't need stakes to be killed, pretty much everything but poison and illness will kill them.
In older games iron/steel weapons did nothing to them if I recall correctly, they obviously changed that in the newer games because it would have made the game way too easy for low level character since everyone uses iron/steel weapons and becoming a Vampire is much easier than how it used to be, it was like a 10% chance of getting Vampirism..and 90% of catching an instant death in a day or two disease if you didn't make it to a temple from them.
One can only imagine how things would have been if iron/steel weapons still did nothing to Vampires since even at level 81 I find bandits and random enemies using iron/steel weapons, rarely I find an ebony weapon or such among them.
...and if I recall only silver weapons did actual damage to werewolves/wereboars, while granted they did make it so silver weapons do double damage to werebeasts.
Ah, if only.