The Honor System in World of Warcraft is fundamentally flawed. Most people expect the Honor system to measure skill in PvP, and it really does not. A Grand Marshal or High Warlord should be the most skilled fighters on the server, and often they are not. The flaw in the Honor System can be summed up as follows (Coriel's First Law of Skill):
If the metric used to measure skill cannot decrease, you are not measuring skill, but time.
Intuitively, this idea is pretty clear. In most other games, your skill metric can go down as easily as it goes up. Consider poker, where you can measure skill with money won. A good player wins more money than an bad player. In fact, a bad player often loses money. And this possibility to win or lose money occurs on every hand. If you could never lose money in poker, the person with the most money would be the person who could play the longest.
Another example is the batting average in baseball. You get a hit, your batting average goes up. You strike out, your batting average goes down. Or how about chess? You win a match, your rating goes up. You lose a match, your rating goes down.
Pretty much every game other than WoW gets this. Yet in WoW's PvP system, your honor total cannot decrease. If you go into a Battleground, or attack another player, you will never end up worse than when you started. And so the people who gain rank are the ones who play the most, not necessarily the most skilled players.
Now, there are all sorts of potential ways to change the metric so it more truely measures skill. For example, you could do Kills minus Deaths. Or Kills per Death. Or Kills per unit time played. Or some sort of rating system, where if you are defeated, your rating goes down proportionally to the rating of the one who killed you. The important thing is that each PvP encounter must be a risk, that your honor should have the potential to decrease as well as simply increase.
Of course, being a random anonymous internet pundit, I have a preferred alternative to the current Honor System. That will be the subject of Part II.