Well, admittedly is doesn't get into DETAILED violence. No, hellsing isn't meant to be disturbing. Ever. Well...uh....haha except for poor, poor Raped Van Winkle. That was both amusing, hot, and disturbing at the same time. But outside of learning why they call him Vlad the Impaler, Hellsing is never really disturbing.
And yes, in OVA5 Seras becomes as hax as Alucard. But that hasn't been animated yet. I guess you'll never like her.
Hellsing doesn't make you think. It's just a funny awesome gorefest with lots of great interesting characters.