This one's kind of a vague suggestion, but it's simply a possible implementation for the House on the Hill - as some sort of 'Mystery' quest.
Essentially, the inside of the house would be your basic mansion - lots of rooms, all filled with stuff. And by "stuff" I mean game objects. Throughout the house, nearly everything you can think to mouse over will produce the little gears animation. The quest proceeds with you running from room to room, through the house, looking for clues - each clue leading to the next. What's more, clicking any object that was not the next clue would produce a different result - sometimes, you find something useful (gold, orbs, loot); sometimes, nothing; and sometimes, it's a trap.
Enemies in an old 'haunted' house could include animated suits-of-armour, animated bedsheet/tabecloth 'ghosts', and the like. I'm not sure what the whole aim of the quest would be (what it is you're actually searching for, overall - something as simple as trying to find the owner of the house would make sense, particularly if he's sequestered away, and you have to find a key or something first), but the Storyline can dictate that - I'm not sute what they're planning to do with the plot, relative to the Vampires, so that would probably affect the goal, on its own.
In general, I've grown to favour slightly less hack-and-slash instances in the game. If you want that, that's fine - you can run through the House checking everything - finding all the little treasures, and waking up every Animated there. If, however, you follow the clues successfully, you can get through most of the House without ever fighting any enemies at all. I like to retain the hack-and-slash option (since that's what the game has led you to expect), but I personally like having more plot-based alternatives, as well...
