I cannot believe how far in advance the story has set itself up. (spoilers of course)

[Raldo]

Given that the Warriors of Darkness were introduced and then whisked away with all the impactfulness of a wet fart, sometimes it feels like they originally planned for Shadowbringers to come before Stormbringers. If that was originally the plan, it suddenly doesn't seem all that surprising to see that sort of content at the end of HW, since it would've been less long-term foreshadowing, and more direct foreshadowing for stuff coming in mere months. (Also I feel like Lyse's SB gear would've made a lot more sense if she had become a DNC, but I digress...)

With that said, I seem to recall it being stated that the whole Bahamut-inside-Dalamud scenario that they used to destroy 1.0 was originally planned for like... expansion 3 or 4 or something, so yeah they definitely do a lot of planning ahead.