One of my main sims is a grand master vampire, so I can sympathise. The power issue isn't something I've noticed as I only ever wanted him to have specific powers which he has already. However, the umbrella issue is a nuisance, particularly as he's not even affected by the sun. I had to remove the umbrella from his inventory to stop him constantly trying to get it out outside. I do wish vampires would react to the change in temperature/seasons though and change their clothing for instance. This probably isn't a bug however, but by design.
