Anyone could do that and it's doesn't scream originality, but what are you gonna do?
Ripoff WW while lying that you aren't?
It's quite entertaining read. It also inspired me to think a bit about how I would make things my way:
1) Vampirism - It's essentially a virus. The more blood you drink, the more likely you are to infect that person. Unless you drink too much, then the result is death. Neither case is deal if you want to keep things under the wraps. Additionally, blood is like a drug for vampires. They have to keep themselves in check while drinking it. Which is harder as time goes on, for obvious reasons.
2) Supernatural powers - You get some superhuman qualities (sensitivity to sun, night vision, super strength/speed, hyper regeneration, unaging, etc.) but I would stay away from something like turning into a mist or a bat. The idea of vampires acting like "spies" in human society is more interesting to me than vampires having superhuman battles at night or somesuch.
3) Relationships - Since vampirism is a disease (with no unique characteristics/powers between each vampire), there are no bloodlines or inherent "Clans" or related powers. Instead vampires organize themselves based on their personal realtionships. Power of each individual and group would depend on who knows who. Oh, and since vampirism is easy to spread, everyone is responsible for making sure new vampires (or vampire-related accidents) don't happen. Otherwise the sanctioned cleaners are going to clean up anyone involved.
4) Secrecy - Vampires keep their activities hidden for a bunch of reasons. It is easier to manipulate people that way. It is also safer than waging war on mankind. The all-out war would have the effect of necessitating the existence of substantial standing army. Considering how blood works you don't want the logistic headache involved or risk demand exceeding supply, so keeping numbers low is better strategy.
To make sure the count stays low and humans are kept largely in the dark there is the Inquisiton. Why the name? Because it was the vampires' idea to start an organization centred around hunting down the supernatural back then for the purpose of maintaining control over it and to use it against those who stepped out of the line. The name (and the title of an Inquisitor) is the reminder of that era. They look more like Men in Black than a wannabe Van Helsings, although I suppose they could cosplay as such, if they needed to make it public and pin the blame on some religious freaks.
I could go on, but I think this is enough to show how I would make my own vampire setting and how remote it is from Vampire: The Masquerade, despite taking the general idea of "modern vampires hidden in plain sight".