Grind? Do you maybe mean just playing the game normally and doing activities in the new expansion? Like, what always just gets you to exalted with these main narrative factions?
Honestly, the only people who are bitter about allied races requiring unlocking are those who don't really play the game actively but just return whenever something "new" is being added to test it out. Or in other words, people who do not invest time in the game and don't ever experience the content to its fullest. I think it's good that these people actually have to put some work into unlocking these races, while those who are playing actively will unlock them pretty much automatically.
I would understand the uproar if they made it a low chance drop from a paragon reputation chest, now that would be funny. Just hitting exalted, not with some obscure hidden faction, but the main faction in an expansion is absolutely nothing hard to do...if you actually play the game.
It would be grind if they suddenly told you to go grind exalted with Ogri-La, for example. Not saying that would be wrong, but that would indeed be a grind. Maxing a reputation from the main content that just gets done naturally is not.