N64 was the most powerful console of the generation, and the GameCube was a little bit below Xbox but well above PS2 in terms of power.

It was? Interesting, never knew that. The more you know.

many people think that but if the fusion concept is true, i really can see a playstation vita / vita tv situation.

Using the same mobile ARM chip in both the handheld and the home console / "tv box". Mobile chips probl wont be stronger then the wii u in 2017 (at least not at an affordable priece). 

There are many reasons for delays or setbacks, but at this point, (assuming home console) if NX comes in weaker than PS4 on a 2017 release, it could be a pr nightmare and we'll never hear the end of it from a bigger part of the gaming community.

If NX is 14nm (2x perf/watt) then expect a smaller, lower powered system that sits somewhere between PS4-4k with the baseline 3rd party lazy ports matching PS4OG.

will be a 4 bit system

Indeed.

gamecube was more powerful than ps2, not by much bit was. 

I would hope that it would be on the level of a PS4 if not a bit more, though it;s been a long time since Nitendo thought power=great games.

their current releases prooving that gameplay/gimmick is more importent for them then graphics (star fox zero).

We'll see how far the next possible gimmick is pushed, if anything it could actually turn out to work for themr ather than against them.