Given a group with 2 tanks, 4 to 6 healers, and 12 to 14 DPS there are 5.97138E+23 different permutations that can arise from different spec selection. If you look only at class then the number is 1.17947E+20.
Five mans run with 1 tank, 1 healer, and 3 DPS as is standard look a bit better at 365,010 permutations for specs and 54,925 class based permutations.
It's a wonder anything is ever balanced at all.
Let us image for a moment that you playing a game of chess. Your opponent is the computer and it runs one of 9 different scripts that determine how it will respond to your moves, how aggressive of defensive it is, etc. The game is to figure out how to beat each one within a specific amount of time. Attaining the quickest time on all nine gives a very nice reward. Attaining a slower but still quick speed gives a reward and finally attaining a certain maximal time gives a final reward. Anytime beyond this maximal time has no reward.
To further complicate things you only move one type of unit. You have a team of players that you work with and they move the other types of units.
So one player moves the King, one moves the Queen, one for the Bishops, another on the Knights, one more on the Rooks, and a final player moves the Pawns. 6 players in all and each of you has to work together in order to beat the computer opponent in a quick enough time to reward you the prize you are after.
The best teams will have players who understand not only how their pieces move but also how each of the other pieces move. In addition each of you is quick with identifying patterns in the computer opponent and suggesting a response to the computers moves and countermoves. Each person has a very good sense of when to take initiative and when wait for orders. If the Rook player sees a valuable move ahead he may take action in order to prevent a set back without waiting for the Leader to issue her command.
Highly skilled, highly motivated, highly responsive.
A step down from this is a team who wait to act until orders are issued. The team members may offer up suggestions which are usually of high value and often executed but they still wait to be told what the action will be.
A further step down is the group who is awaiting orders not simply because they lack initiative but also because they have specialized in their own piece and have little understanding how the other pieces work or how the pieces interact to create an overall strategy.
Some groups lack a full 6 player roster who take the time to learn the computers tactics and thus wait for orders from those who are more astute.
Some groups have too many players who have a strategy in mind and lack coordination which results in players moving on top of each other making the strategy much more complicated.
These groups are typically composed of only a few players who truly understand each pieces place within the larger strategy and instead play mainly from hubris.
There are also the groups which have within them the players who either forget the more complicated moves their piece is allowed and thus must be reminded or they simply do not know the piece at all and await commands that require much more detail than better players require. This is especially detrimental if the Leader is focused in on his own piece and fails to properly utilize the other pieces.
For any wow group from a heroic scenario team to a challenge mode group and on up into the 20-25 man heroic/mythic groups this is even more complicated. Suddenly each side moves in real time without waiting for each to take their turn. Tanks, healers, DPS each have their own sets of abilities in addition to personal and group utility. There are 34 different specializations that must be considered. Besides the core abilities of each class there are a host of utility spells that see little use from unskilled players and are easily forgotten.
I'm often left wondering at the end of the night how well I moved my piece and whether I could have done more. Worse is my internal questions about the competency, initiative, and skill of those around me.
Did I properly motivate them to take the initiative to point out flaws and suggest solutions?
Are they passively sitting by and awaiting orders that may never come?
Do they understand their piece well enough to offer up suggestions and solutions that I couldn't possibly think of unless I took the absurd route of learning all 34 specs and all CDs?
Did they put forth enough effort into self preservation or did they die not because I failed them as a healer but because I failed to motivate them to put personal survival above any other order?
These are the doubts that linger in my mind and keep me awake at night. Am I good enough? Am I far behind their skill? Are they good enough? Are they far behind my skill? It is hard to know the amount of effort some are putting into an endeavour. Whether they are simply showing up and hoping for the best or going to amount of extra effort to improve our chances of success.
Its a very difficult problem for a leader....especially a leader who wants more than anything to be surrounded by highly self motivated individuals who are keen to overcome problems and offer up solutions....if only because the burden of leader is scary and the leader fears failure.