Ghostcrawler has repeatedly posted flawed logic why he thinks Tri Spec is bad. If he used this logic consistently then there never would have been duel spec since having two specs takes away from the unique nature of the character.
Also, that is another point, are you playing WOW or is your character? I mean this, when I play, people know me and know that I have many alts. They want to play with ME and it is one of my alts that will determine what character I play, i.e. tank, heals, dps. It is THIS reasoning that many people wish Tri Spec, so they can play with their friends and not worry about the character. Another way to put it. It is more important for the character to play or the person behind it.
The character is NOT the most important thing in the game, it is the PERSON behind it and if it is easier for friends to play together because of Tri Spec, just like the same reasoning as duel spec, then blizzard needs to take off the blinders and realize this.
Lastly, as a company, they need to realize that the needs of the customers means more then unilateral thinking on their part. I believe one reason why they lose people is that they are not as concerned about the customer as they should be.
Just a thought.