Both Wrath and Legion were culminations of story told in Warcraft III and Frozen Throne, especially Wrath is pretty messy without that foundation (imagine last hour of LoTR starting with tournament in Mordor and Sauron randomly showing up there).
Shadowlands are completely on the opposite, it's strange to me that Wrath nostalgia is so underused if this is continuation of that thread anyway. You clearly see that potential in Uther storyline that is arguably best thing connected to main plot.
And yeah, Legion was great with end of raids big events - Illidan resurrection, Argus showing up on the sky (we all knew this will be 7.3, but no one expected it visible on the sky all the time) and sword in Silithus. Let's hope 9.2 will have some return of form in this field, cause last few cinematics were full of missed opportunities and made you feel "that's it?" instead of "hell yeah" (but don't forget it's WoW community and there is always shit ton of people saying "that's it?" even after Antorus end).