I agree with you about today. If Apple had chosen to do big today after releasing the new awesome M1's, it could have created even more Apple fervor, especially for this considering their first iPhone, Mac, Apple Watch, or iPad. Apple chose (probably last year or earlier) what today was going to show. As an end consumer, I am happy with today. It didn't wow me but, I wasn't looking to be "wow."
I do think expectations in MR land were off the charts. I think a lot of that was due to editors fueling the fire and forum members convincing themselves of a perceived truth that was never there to begin with.
As to the last time Apple went big with features, I think that that is rather subjective and what you or I consider big (or not due to disagreement) may be different for others here.
With today, I think the new features related to privacy and security with Safari are big. That may not even register on the 'happy' meter for many here but, I embrace it. While not it may not be an Apple magic feature, I think the health features today were big in that they will provide a more balanced medical profile for the user as well as family members. I see the direction Apple is going in that department and I like it.
As to previous presentation releases, I think Sidecar was big. I think silence unknown callers was a big feature. I also consider app tracking to be a big feature.
With the watch, I consider fall detection a big feature along with blood oxygen.
I could mention more but, no need filling the thread.