Eh. People who think Nintendo stole the show outright or changed E3 forever are on the Kool Aid a bit. They might have had the best showing, but it's more because Sony screwed up their presentation than Nintendo had a crazy great one. What Sony actually had to show, in my opinion, was at least as interesting to me as what Nintendo had to show.
Most of Nintendo's showing looks like quantity over quality. All of their new franchises were C-tier at best, most of their brand new games are eShop-looking titles being sold at full retail price, and their game reveal method was awkward and annoying (a 45 minute Direct followed by a 30 minute hunt of find the news, with one reveal or two the next day max). They didn't commit to pushing all of their announcements all at once, and they didn't commit to spreading them all out -- they had an bad in-between.
The Treehouse thing was good, but people saying this is a revolutionary event to change E3 forever are on drugs. The press conference is going to die in the next few years regardless of what Nintendo does, and although they had the best stream, they were far from the only company with an all day stream. This just shows they had the best head start.