In my opinion this year is the 3rd best. 2nd best was 2015. That whole puppet thing and the whole video was amazing. Last year, 2016 wins though. One game, but it was so hyped so much. Totally showed off so very well.
Uh......
2015 was the "dark" ages of Nintendo. Yeah, the puppet thing was cool, but E3 was about games. And the games... Well....
Star Fox Zero- A very flawed concept from the very start, so much so that professional developers couldn't envelop proper game design for it. People who played it on the show floor hated it, and it looked very underwhelming. I had still had hope that it was good: but it was hardly hype worthy.
Triforce Heroes- A multiplayer 3D Zelda game. Which was actually pretty decent, but by no means exciting.
Mario Maker- Arguably their biggest game of the show, but it was pretty good.
Animal Crossing Amiibo Festival-trash
Mario Tennis Ultra Smash-trash
Mario and Luigi Paper Jam: Yet another rehash, and it is the worst M&L
Xenoblade Chronicles X: A game that has been out in Japan for 2 months already, the only thing we saw was the release.
Yoshi Wooly World- A good looking 2D Platformer
2015 was really one of the most disappointing E3's since 2008(As an aside this was also my first E3 that I watched... What a train wreck that was).
I have no idea about you. But I would take
An expansion of what many call the greatest game of all time(BOTW)
Metroid Prime 4 Announcement
Pokemon on home console Announcement
2D Metroid 3DS announcment
A true, full blown 3D Mario Game
Another Xenoblade game, this time getting a worldwide release on the same day
A multiplayer Kirby game on home console
Yoshi game on Switch
Fire Emblem Warriors
Splatoon 2
Mario and Luigi Superstar Saga + Minions
I suppose you have really noticed a pattern. Yes. E3 2017 covered many of the same franchises as E3 2015, however, the quality of the games drastically matter to the conferences. E3 2015's were middling at best, egregiously terrible at its worst(with 2 exceptions, being X and Mario Maker). Almost every game at E3 2017 has the potential to be one of the best games of their series, or even one of the best games of their genre. This E3 had genuine excitements and innovations to their respective franchises, in a way where many games were completely stagnant. Nothing was really done to evolve the series in Paper Jam or Triforce Heroes, for example, and these games were largely forgotten a mere month after release. In E3 2015, if you weren't a fan of Mario or Xenoblade, you would be extremely dissapointed. E3 2017 had something for almost any kind of Nintendo fan, and had quality games that they could enjoy for a long time. SO I really don't see how you could put 2015 over 2017 by any stretch of the means.