To start off with a bit of a summary, before Nintendo's Digital Event I was like "meh" about E3 in general this year. At that point, I had only seen Microsoft's press conference - not Sony's, nor other publishers' as I didn't care enough about those (plus IIRC Sony's was at 3, 4 AM local time or something) - and MS only had one game that really looked interesting to me, which was Ori and the Blind Forest. Well, I guess Sunset Overdrive looks pretty cool too, but neither of them is (nor are both together) enough to make me want an Xbox One.
Then, Nintendo's Digital Event kicked off. I really wasn't expecting much from it, I guess just some news on Smash Bros., maybe the new Zelda, as well as other stuff already announced. But what actually happened is that they've pretty much sold me on the Wii U now! Smash Bros. I wanted to get for the 3DS - and still will, because it comes sooner and I'll only be able to get a Wii U next year at the soonest - but I also want it for Wii U. The new Zelda I honestly wasn't sure about, and maybe still am not, as I didn't like Skyward Sword very much, but that's another one that might shape up to be pretty awesome. I mean, a true open world Zelda, if they can really pull it off? Hell yeah, I take that! Now, Xenoblade Chronicles X I'm a bit divided on. Not because of it's quality, as what I've seen of it on Treehouse Live @ E3, which was the first 30-40 minutes of the game, seemed really impressive in all respects (visuals, sound, gameplay, world, etc.), but rather because I'm not sure if I'll be able to get through a game of that scope.
Another game that just looks insanely fun is Splatoon, which has also been demo'ed extensively on Treehouse Live. It might also be the game I'm most excited about right now, for some logically unfathomable reason: all they've showed was 4-vs-4 online play, in a single game mode, on a single map. But that alone already had me wanting to play it that instant, and still has me wanting more. I do really hope the devs extend this one with more varied modes, etc., tho, and that Nintendo actually pushes this one with some marketing muscle. Otherwise, it has the chance to end up as a limited throwaway title, and I'd hate to see the ideas and the design in this go to waste.
Yoshi's Woolly World and Kirby and the Rainbow Curse also look pretty fun and very unique visually. Granted, we did have the yarn style before in Kirby's Epic Yarn on the Wii, but Epic Yarn looked quite flat compared to the more "popping" Woolly World, with Yoshi, the enemies and bosses looking like actual three-dimensional plushies. Rainbow Curse I'm quite happy to see, just for the fact that it uses the indirect control scheme from the DS' Kirby Canvas Curse again. Pair that with the new game's clay look, and you've got an interesting game from both, the visual and gameplay perspectives.
There's also been Bayonetta 2 and a new Star Fox for Wii U, as well as Codename S.T.E.A.M. for 3DS, all of which I haven't seen very much footage etc. of yet so I can't really comment on them, outside of saying that they might be interesting as well from what I have heard. Bayonetta 2 will also include an enhanced port of the original Bayonetta for free, so that's another plus for someone who hasn't played the first one yet (i.e. me).
And while I didn't want to focus on Nintendo alone this E3, they've done a great job keeping people's attention on them and their products, with the aforementioned Treehouse Live livestreams every day of the convention. They've provided some, from my side very appreciated, additional insight into upcoming games from Smash Bros. over Splatoon, to Xenoblade, had developers on explaining things - both first-party and indie devs - and even engaged with them in multiplayer shenanigans - four of Splatoon's devs wiped inked the floor with four of the Treehouse guys, for example. That Smash Bros. Invitational tournament they hosted was quite the cool idea as well. I'm not into competitive gaming of any kind, thus including Smash Bros., I just know that it exists (and that they swear on GCN controllers for Smash), so I had no idea who was who in that tournament, but it was great watching players of that skill level, and I wouldn't mind seeing something like that again.
Finally, as much as I was wary about their approach of forgoing the traditional press conference, I think they've done a great service to their fans and anyone else willing to watch and listen with their coverage this year. If this worked as well with non-fans and the like, I don't know - time will tell.
(Whew, took a while to write all this...)