1. I was never allowed to go on FFXI raids because I didn't have above basic 75 gear. So that point is invalid, their will always be elitest, with or without addons its a manner of players once they find a way they will implement it. Just like they do now "Oh you are a PUG without such and such cross-class ability?!?!?! GTFO! Level your other classes!"

2. Blizzard took the gear score thing on board and now it is displayed on gear last I checked. So no add-on required, heck I had read a early cata dev post saying in next patch we will be releasing so-and-so gear score items so you can take on the next dungeon. It isn't an add-on's fault, blizzard just made WoW gear specific on content as to artificate some of the difficulty and give the endgame players something to strive for.

tl;dr Don't blame add-on's for either game design or player community, if you don't like it, continue playing the game the way you want. Don't play with those people, because they ruin your game experience.