How its a new concept if they did it since the beggining?
I guess what I mean is identifying Dracula as actually being Vlad instead of just using the name (other than both being Romanian nobles, there's not that much in common- Vlad was a Wallachian and the Count is a Transylvanian Szekely). 20 years ago identifying Dracula as the historic Vlad the Impaler probably seemed novel, but it's almost become a cliche unto itself.
On top of that, I think it's a little problematic giving a character like Dracula a solid origin story. Maybe the character WAS Vlad, maybe he was just an itinerant vampire looking for a castle and liked the idea of being called "Son of the Dragon/Devil". In the west we definitely have an overbearing need to know where something comes from, but I like the idea of Dracula having mysterious origins.
Although if Dracula IS supposed to be Vlad, that certainly throws an interesting light on his niece being Elizabeth Bartley/Bathory.