This is a huge problem in my
opinion. It's not just that the numbers are too big to fit into 32-bit signed int (the engine uses 0 HP for dead and -1 for Ghost, so I know it's signed); there is a more important reason.
The numbers now are getting
so large that it is becoming difficult to identify what attacks are hitting you and for how much. Telling the difference between 3 and 4 digits is much easier than telling the difference between 5 and 6 digits. The numbers have to lose precision due to writing things like kilos.
I've decided to make an addon that divides all numbers displayed on screen that have anything to do with mana, health, damage, and healing by 30. I can change this number any time I like.
Takes care of the problem handily.
In my opinion they need to do a great item squish before the numbers become literally unreadable. Either that, or they have to add an option that allows you to divide displayed numbers by something you specify, like my addon does.
EDIT: This is what it looks like:
http://i.imgur.com/3poJ3Ug.jpg