Nobody says quests has to get removed, they just have to not be mandatory for entire expansion, even vanilla didn't require you to do THE SAME quests for its entire lifespan.
And I doubt I will be able to complete callings via M+ like I could do so with BfA (since no quest could be done in M+), but I could be wrong. Having them done via M0 for geared character is dumb anyways. Not to mention some of the calling specifically says about completing WORLD QUESTS. And as far as I know they are random.