We all know items have a "budget", and out of that item budget they assign stats, DPS, resiliance, activated abilities, procs, etc.

I'm just wondering, do the classes have any such "budget" to help design them? I know classes are more free flowing than an item could ever be, but it seems to me as though a certain ammount of HPS/DPS/mana efficiency would be worth X points. A wildly usefull Y duration would be worth Z points, etc... Stuns might be worth Apts for every second they last...

Just wondering how these classes were designed and balanced, and what if any toold blizzard uses.

We have budgets for the power of individual spells and talents. We do not budget based on the total number of abilities available -- some classes just have more than others.

I would also call the budgets a guideline. You have to know when to change the numbers on something even if the budget suggests that will be overpowered or underpowered.

To be metaphysical for a minute, you can't define the universe with one gigantic equation. There are just too many variables. You can use simpler equations to attempt to describe small parts of things as long as you understand their limitations. A great deal of your success in WoW, perhaps even more in PvP than PvE, is your skill in using your abilities and that is a hard thing to model.