I actually love that the needs deplete so slowly because it gives me a lot more flexibility to focus on doing more fun stuff with my vampires. I see vampires as higher on the food chain than normal sims, and not quite alive, so it totally makes sense to me that they don't stink or deplete as quickly, save for their plasma lust.
But I can see why it's inconvenient for you. Maybe you could try taking some challenging weaknesses, it might fill in that gameplay gap for you. I see the weaknesses as a great mechanic put in place to replace the need challenges to keep vampires from getting too easy or powerful. You might end up enjoying them. :)
