First off, we have the "laggy" transformations for the vamp lord. This lag is not what you expect. You see, when you turn into a vampire lord, EVERYTHING you are wearing is un-equipped or re-quipped, depending on if your turning into a VL or turning back. Now think. You have a full set of armor, a ring, a necklace, and possibly a mask. Un or re-equipping all that at the VERY SAME TIME will cause lag, it's impossible not to. You console players have all experienced minor lag when putting armor on or off, I am sure of it.
Second and final are the complaints of not being able to open chests. Why is that? I can answer. When you turn into a vampire lord, you are changing your species into a whole new one. The humanoid species' you know and love are built with inventory's. The vampire lord species does not have one. That is why you cannot loot chests, because your species doesn't have an inventory to put items into. If you could loot chests, you would have two seperate inventory's. Would you REALLY want to switch between the two constantly for reasons so massive I cannot even begin to describe for you? NO.