They'll launch it in March 2017, that's in 6 months if it will be in the second half, anyway, 5 or 6 months doesn't change much, but they cannot start advertising and PR full steam before Xmas 2016, otherwise they'd kill Xmas sales of current products.
I expect revelations and advertising to really start next January, and probably more hints than now already in the next months, but not so many to spoil 3DS Xmas sales.
Yes, Internet awareness isn't  equal to full mass awareness, but nowadays it's already become quite close to it.
Not to mention that launching in March, NX will have two big marketing campaigns in its first year, for launch and for Xmas 2017.

Giving us the chance to make a new rumour each day and we can hold on to the idea of the NX being the best (Nintendo) console of all time.

So... they should have announced it as everyone was focusing on the new PS4? That's a brilliant strategy. I'd be fine not hearing anything about the NX until January. That month is Deadzilla as far as gaming goes, so they will have everyone's undivided attention. And then they can steamroll market the heck out of the machine, building up hype for 2-3 months before it gets released.

There is one problem, will people get the concept of the NX in time. You can release a PS5 and announce it a month before it launches and over a million per orders are placed none the less.

There NX is a different story it's a new concept and for this moment we don't know how it works. Nintendo should take the time explaining what the NX is, how powerful it is, how it works and why we shold buy one, Zelda alone is not gping to do it. If they don't do that they could have another Wii U failure or at least something comparable to the Xone launch.

The NX is more relevant and important than a new PS4 though. Besides with all these PS exclusives bring delayed January might become intresting after all. Sacrificing a holiday is never a very good idea though. I doubt many 3DS or Wii U units will be sold this Christmas.

Point is that today you relly dont need more than around 6 monts to revile your console before launch , XB1 was revealed 6 monts before launch, PS4 Pro only 2 monts before launch, today companies want shorter time before revile and launch of product, it has much better effect, you can easily mantine hype and interest from revile to launch.

Wii U was revield one year before launch, and had teribile revile, first impresion and marketing, with NX they dont need to revile it too soon and they already said they have new "concept" and "new way of playing", so from that side they also want to predict NX, very strong NX NDA (sources saying NDA is stronger than ever before) proves that. Curently is all about right timint of revile, I am sure NX will be revile sometime in next 4-5 weeks.

It's not really doing Nintendo any favors. I wish they would just reveal it already... I fear if they wait too long, they're have to delay the release of the console, and I don't really want that.

Yes, clearly Sony copied Atari in '97.

Actually that is a good example of why Nintendo is being secretive.  It took Sony one year to implement Analog, and similar time for Sony and MS to implement motion. Announcing a new innovation now could give MS enough time to include it with Scorpio.

No point in showing your cards too early, competition can and will copy a promising idea. Also we know how fast news spread nowadays, so there really is no significant problem in having the reveal a little bit closer to the actual launch. Keep in mind that while March 2017 is the first target, the launch date isn´t set in stone yet

It wasn't just motion controls that saved the day with Wii, it was motion controls, a killer game, and a low asking point of entry into the experience. 

Unfortunately (or fortunately, depending) Sony didn't copy that.