I don't even remember whether I have used Vampire to get VT badge for Hard GT (got the badge, but don't remember which class I used to get it). I think there is still "a significant amount of difference" with preps - RBS (for Horatio), Dragon Shield (Resists really helps Vampire), Patches (for more Resists), Whupaz (for H), Burn Salve and Fortitude Potion (corrosion and weakening really hurts the Vampire).
Luck also plays a big part, if you can get the Bridge Troll, the extra levels of Lifesteal would definitely help. Not saying it is not possible, just that it would be really hard.
Sidetracked a little, so I also wanted to get Gorgon out of the way,


At least I tried to do it somewhere other than Hobbler's Hold, wouldn't want to hurt poor Lord Gobb anymore,

Dracul definitely is powerful, I "underestimated" the powers he could give, and thought at first it would be tight and I would need to convert to GG to spam Fireballs to finish off the boss. In the end, this wasn't even needed.