I don't know the accuracy of this statement and I have no way to go back and test it. Here is what I think may have happened to the vitals box.
When they changed the way the debuffs and the buffs work how they list the shortest cool-down on the right to prevent them from moving around so much it made the vitals box it's current size. I do not know of any skin that can change the base size of any ctrl-\ boxes.
That's my thought on what caused them to increase in size. I would like them to be shorter then they are because I keep mine on the bottom of my screen.
I looked through the xml file and I can't find the line of code to change the vitals box. Would you please post the portion of the code that I would need to paste into the xml file that I'm currently using.