Nintendo made a decision a long time ago that their world doesn't revolve around E3 and I think it was a smart decision. Throughout the year we are getting Directs which reveal new games. If Nintendo decided to save these all for E3 announcements then it would have been a stronger showing for them. E3 is mostly for the AAA market to flex.
I think that the presentation would've been stronger with Smash in the middle, a more extensive look at the third party games shown in a hurry, and a surprise announcement to end. I also wish that there hadn't been so many leaks, as Fortnite would've been a major bombshell if it wasn't leaked beforehand.
But I agree about the Directs. They are so much more enjoyable throughout the year because they are announced on short notice and always include something unexpected. This one got lost in the crowd at E3 and just wasn't tailored enough to the E3 audience to be satisfying, even if what was shown will drive console sales more than the stuff the E3 crowd goes crazy over.
The 1-2 punch of BOTW and Odyssey satiated traditional gamers in a way that is almost impossible to match, but releasing Mario Party, Pokemon, and Smash in consecutive holiday months on a system that also now plays Fortnite is going to move far more consoles than last year's lineup did.
Switch won't even be two years old this Christmas, and its first party catalog alone will include Zelda, 3D Mario, Pokémon, Smash, Splatoon 2, Mario Party, Mario Kart, Donkey Kong, Kirby, Mario Tennis, and Xenoblade. It's going to be a holiday for the ages.