Surely something happened, there are way too many hints the original release was going to be this year, and probably they had a major NX presentation in mind. But I don't believe there are such insane problems for the software that they couldn't show anything at all already at E3; otherwise, we wouldn't have a release for March 2017 already, around 3-4 months after the supposed original date. It doesn't make sense at all. And we know about SDKs getting distributed to "key partners" at least since last October, and we have Square/Namco/Koei among those "key partners" for sure, at least (I mean at least because we have statements / good hints for them), plus a schedule for a broader distribution of dev kits. Not even talking about how some third parties had talks even before E3 2015 for the platform. So, technically, given the amount of the delay, I'd say it's nearly impossible that, while something must have happened that changed their plans, that something was so brutal that they can't even show trailers of NX games, or have playable builds with, at least, some of their own titles. IMHO, there's another reason, like...the scheduling. Basically, they really want to keep everything secret as much as possible, and to unveil the thing + games in a fixed amount of months, due to how they were already planning the after-reveal advertising machine and all that. So, I suppose that, with NX now "delayed", all that scheduling has been delayed as well. Now, the event they had in mind at E3 is delayed too. ...Or maybe there was going to be an event before E3. I mean, don't forget how Orgen implied, more than one month ago, how we would've known more about NX before E3. It's entirely plausible he got told about the investor briefing basically, but what if that event was something different, and that was going to happen before E3? With all their booths dedicated to NX at E3, after the first unveiling? That would make sense as well, I assume.
Anyway, again, I find it completely implausible that they were in such a state they couldn't show / have playable builds for anything at all when the console releases 3-4 months later than when we all supposed it was going to be out (with several solid hints on the matter).