The negativity and fanboying in this thread 
I wouldn't say Nintendo is in the perfect position but they are in a pretty good position. When people think about E3, people think surprsing game releasing and new surprise features. Between Xbox One and PS4 there were minimal suprises (majority we've seen/knew about since their respective conferences) that's why (as someone else mentioned) people feel PS4/Sony won because no region free, $100 less, FFXV, KH3 and a few others were some really good surprises that would entice people to think PS4 is leagues better than Xbox One (which in reality they are still in the same playing field and had a similar conference just a few different exclusives that aren't as make or break as FFXV, KH3, and Halo).
Now Nintendo already has the element of surprise on their hands with games that we haven't seen for quite some time (Smash and Mario Kart), show off the stuff coming very soon yet we don't know much about (Wind Waker HD, "X") and perhaps bring in new and old IPs that could assure the short term success of Wii U. Frankly, 3DS is already doing its own thing so there's no need for doubt on that side of things. The issue is Wii U and today could put Nintendo in the position to have a good lead on PS4 and Xbox One if those long term surprises come sooner than expected and catch attention today. It would place the undecided gamer to consider buying Wii U sooner rather than later since the good stuff is finally trickling down.
This conference moreso will put the immediate need of a Wii U on high rather than waiting for PS4 and Xbox One to come and murder what's left of Wii U. So, Nintnedo won't necessarily win E3 but they will "win" getting Wii U into a position to play against PS4 and Xbox One in the long and short term.
