I don't think that there was a need to discuss Dynamis at all for the main conflict to exist. The Final Days dates back to Shadowbringers. There also wasn't a need to discuss Dynamis to resolve the main conflict. That comes from the Azem soul crystal, Bunny Magic, an irritated Ascian, King Bowser, and the power of friendship. All of these things were also discussed in previous expansions. Dynamis just provides an interesting framework that links these threads together, while also adding to that sense that there's a lot more to the world that we just don't understand yet. It's also one of the few ways that you can justify something being stronger than Azem at this point, since brute force by means of Aether manipulation doesn't seem to work. Something that properly has mastery over Aether and Dynamis, on the other hand...

I think that it's going to be a good jumping off point into whatever comes up next.