They've revealed more than Sony has at this point. What exactly more could they have shown?
It's still 18 months away from launch.
That's the problem. They should've either shown more or less (as in mysterious hype, followed by soon).
Imagine your girlfriend teasing you with a blowjob. You're ready, you've been saving up and the sexual tension is high, she comes closer, pulls down your pants and.... literally just blows some air on your dick. And that's it. That's what a lot of people are feeling like right now. It feels either like too little or too much. Should've instead kept the tension, instead of making people feel blueballed.
That doesn't mean all doom and gloom. Sony aren't there either, so the next-gen is completely in the air yet. Meaning that the E3 isn't as important to do well in (and Microsoft didn't do bad, as they had a lot of good games, though sadly some games were too driven by cutscenes). But people were expecting more. Now, in the end, what games they'll bring for the reveal of the next console, the software, the hardware, the features, it'll all be what'll determine how I go the next gen. Phil Spencer and Microsoft has done well to get back on the horse after the Xbox One disaster of a release year and they've done well in showing they want to provide value to consumers to bring them in.