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From what i read they have doing this since 2 years ago. And if i remembre correctly, even when they had press conferences, they did a press event for the business partners.

Announcing that we'll see 2016 isn't surprising.
Iwata already said they had unannounced games to come out until March 31st, 2016. And we can also see one game or two for the next fiscal year, too.

I guess they will start preparing them for the Fusion/NX inminent release in 2016.

This is interesting. Will they do some kind of closed door presentation like they did with Star Fox last year? Maybe show off Zelda U to a handful of folks?

This happens every year, and not just for Nintendo. This is where the retailers, distributors, etc. go to learn about upcoming products, so they can order appropriately. Don't forget that E3 was originally just a trade show: these presentations, not the public conferences, were literally what the event was originally created for.

I believe that was the developer roundtable, which is a different event.

Yes, exactly. Quoting for emphasis.

is anyone else kinda hoping they announce an fzero pack for mario kart with captain f as playable?

No.

So far it is the same as last year. Their was some media that went to their business presentation but they don't usually cover any in news that most fans would be interested in.