Not according to your definition it isn't. Perhaps you need a different definition of gimmick. I could care less if it makes a system sell better or not.

I didnt make a definition of a gimmick, I know what a gimmick is.

So HD graphics are a gimmick then?

Ok. That isn't the definition you bolded as the definition in you above post. I like this definition much better because it's like your admitting that motion controls are "cleverly and originally devised and well suited to its purpose" as signified by the use of ingenious. I like that definition a lot actually.

Youre desperate. Thats called a natural progression. It keeps generations fresh. 

The Wii Mote is ingenius, but next generation Nintendo is using a new gimmick. Nintendo likes using gimmicks to keep their consoles gameplay fresh. The other consoles stay the same but change the power.

But the Wiimote kept this gen more fresh than the HD graphics...i dont know, it seems that you are twisting that definition to match your likes...

The thing is, motion controls (when properly applied) are more than just a novel scheme to increase appeal.  They can actually better the experience for certain genres such as golf or bowling, not to mention pointer controls making FPSs far more enjoyable (for me anyway).  You wouldn't call d-pads or analogue sticks gimmicks even though basic 8-way joysticks were the prior standard, would you?

The perfect example of a gimmick is the 3D in the 3DS, as it fits the definition to a tee.

The Wii Mote made gaming easier for families who hate the complexities of gaming. It ushered in competition from Microsoft and Sony to see who could dumb down gaming the most. As usual if a proven novelty shows itself large sums of money and casuals with fleeting interest shall follow. Expect Nintendo to pander to the core this generation since the casuals are used up. Even though Nintendo takes gimmicks seriously, it like most gimmicks will be a temporary fix. Microsoft took the rest of Nintendos casual momentum with their gimmick in 2010 with the Kinect and Nintendo experienced their first loss in 2011. 

Motion controls did remove the complexities for sure, but they also did more than that for the market as a whole.  Like I said, you wouldn't call analogue sticks gimmicks, as they became prevalent in the market; so will motion controllers/cameras be a part of gaming in the future as well.  Imagine when motion controllers are 100% accurate or when Kinect works flawlessly and gives people a true "Minority Report" type experience.  These things aren't going away; they're only going to improve.  WiiU still supports Wii remotes/motion+ and Kinect 2.0 is inevitable.  The mass-market appeal shows us that motion controls won't just be relegated to the 7th generation.