WoW offers many ways to play. Within this one game you can find RP, soloing, 5mans, 10 and 25man raiding, BGs, Arena, world PvP, dueling, world exploration, socializing, farming, grinding, AH playing, and twinking; and these were just the ones I could think of in the past minute. One thing I enjoy, however, is theorycraft and min-maxing. I'll give you some basic definitions from wowwiki and wikipedia and come back after the break.
Theorycraft is the attempt to mathematically analyze game mechanics in order to gain a better understanding of the inner workings of the game. Depending on its complexity, certain random factors might be left out, resulting in a less representative outcome.
Min-maxing is the practice of playing a role-playing game... with the intent of creating the "best" character by means of minimizing undesired or unimportant traits and maximizing desired ones. This is usually accomplished by improving one specific trait or ability by sacrificing ability in all other fields.
Now everyone min-maxes to a certain extent. You don't see any Rogues or Warriors running around with Intellect gear (I hope), nor do you see casters with Strength. Why? Because those stats would be a waste. Each group would benefit much more if those item points (the currency that Blizzard uses to determine how many stats should go on a piece of armor of a certain item level) were spent on different things.
True min-maxing comes about when you are trying to find out which of your beneficial stats are the least or most potent. This is where theorycraft comes in. For a Mage, how much Spell Damage will increase your dps by 10, and how much Haste, Hit, or Crit would accomplish the same thing? These are the things that the forums at Elitistjerks.com work out.
For a Mage, however, or any other dps class/spec for that matter, theorycrafting is a fairly straightforward thing. The dps classes and specs have a very one track mind. All they care about is damage. If something doesn't help them do damage, they don't care that much. Thus, precise formulas and ratings can be calculated to find which exact spec does the most damage, which stat is the most valuable per item point, and what kind of gear they should focus on. To the dpser, theorycraft is a science.
For healers, however, theorycraft and min-maxing is not so precise. As a healer, my job is to keep my assignment, usually a tank, alive. How do I do this? Healing is an important stat, making my heals more potent and allowing me to keep up with the damage my assignment is taking. I can't just stack healing, however. If I run out of mana due to lack of MP5 (or Spirit or Crit for Paladins) then I've failed, since my assignment isn't going to last much longer. On the other hand, what if my assignment takes an unlucky hit, perhaps a crush? Maybe I need some Haste to get my big heal off faster to top him or her off. Haste, of course, increases my mana consumption if I'm making full use of it, forcing me to take more regen at the cost of Healing, and the cycle continues.
Thus, for a healer, theorycrafting is more of an art than a science. We must maintain a careful balance of longevity (via regen), throughput (via healing and haste), and burst (via haste and certain spell/talents). There are no formulas that we can use to determine what the balance should be, and it changes depending on the fight. Some fights may be longer and require more regen, while others could involve massive incoming damage and thus more throughput. It is up to each individual healer to determine what balance of stats and what talent spec is right for them, though theorycrafting certainly provides the foundation of these decisions.
Tanking, in my opinion, falls somewhere between healing and dps in that its theorycrafting is part science and part art. There are precise stat requirements that one needs to become uncrushable or uncritable. Certain fights require a minimum amount of health, or a minimum of tps. Once these minimums are met, however, each tank can begin to take a different path. Perhaps he or she will take the maximum effective health route, or the mitigation path, or the avoidance road (ran out of decent synonyms). Perhaps you want a dps weapon for increased threat on some fights, or you really need all the health and avoidance you can get in order to stay alive. These choices are part of the art of tanking theorycraft.
In the coming weeks, mixed in with the WotLK analysis, I hope to post a few things on the basics of game mechanics. This is part of the reason why I wrote this post. An understanding of the decisions that dps, tanks, and healers must make when it comes to gear and talents is closely tied to the way in which the game combat works on its mathematical level.