Meh. it gives the Volkihar a significant edge over other Vampires and explains why they are the strongest in Skyrim though it sort of makes me wonder if...the Volkihar are the original Vampires ever created..I mean Lore wise the original vampires were set in Skyrim so wouldn't they be the strongest since they are the first but its said the Volkihar are the strongest?
Its plausible the original Vampires took on the name of Volkihar as the name of their clan also they are apparently the only Vampire clan that we know of with Pureblooded Vampires...the only other Lore one is the first ever Vampire.
Volkihar might of took the name of the original as you said. Though they are the strongest in Skyrim, but not in Tamriel. And there may be other pureblooded vampires out there besides the Volkihar. The Grey Prince inherited part of the Dark GIft by his father from birth, who was a Cyrodiilic Vampire. Perhaps they too can be full blown purebloods too, though he was a hybrid.
Serana looks like she got turned into a Vampire at 18 so shes had 4000 years to perfect her 18 year old attitude.
People's personality doesn't change with just age, it changes with personal experiences. Serana might as well been 18 and put into that monolith. By all means, for her it felt like a day had passed. She is the same because she never really went out there and matured enough. Time went by and she remained the same.
If i slept for a 1000 years i would be well over my "daddy issues"
Not when it would feel like a single day.