To be fair, this can be said about almost every supporting NPC in WoW - if you just blow through the game without paying attention to the story, none of the characters will stand out to you, and I wouldn't call that a failure on the games part, but on the players.
Using too recognizable characters (Muradin, Thrall, Watchers) is a double edged sword from a narrative standpoint, and one WoW has been struggling with for awhile. As you continually put the player on a pedistal, and in charge of more nad more renowned characters, you're pushing them against a narrative ceiling. With the point we are at now, few characters can even hope to contend with us. Obviously some players like this, but narratively it puts us in an awkward place. Consider, if Muradin or Magni were our follower, as some would suggest, it's essentially putting us above kings, leaders of an entire race of people.
Regardless on your particular view, the point is merely to make an effort for the Warrior Class Hall to encompass more than just one subset faction (Vrykul) in the game, even if you personally don't recognize the characters. If anything, it's encouragement for you to do some research and learn about why these characters are important, I have a feeling some may surprise you.