I have the same type of rotor, but it came with 1/8" shaft. Here is the deal, the magnet is too strong and it causes a higher Io current which have shown it will cause motors to over heat. With that in mind, that rotor assembly will work best with a lower Kv motor of around 1000-1300 to keep the Io low. Hacker and Lehner uses a lower strength magnet (Different material as well), but it works out great. Not always using a stronger mgnet will make it better.

Is their any possible way to demag the rotor to a certain point?

Not without complex machinery. :/ The stronger rotor would be best with a slotted stator, I would think, because there would be better magnetic coupling between the windings and the rotor poles.

Or heat to a certain extent?

Yeah, but how would you take an accurate measurement of the remaining gauss? And you would have to cool it down almost instantly to seal in the rest of the magnet's strength so it didn't lose too much.

Maybe trying different Airgaps to find the most effective one to make such a strong magnet work to its fullest. All the 2 pole motors I tried with similar cogging has failed.

Is their any way we can step down the strength of the rotor in a way that wont harm it but will make it run more efficient. And a way that will not be expensive and something maybe dummy proof.

Best bet is to try a low Kv motor or try different Airgaps.

I already have two motors on my hands I cant send back.

Bulding a motor is not as easy as you think it is. Slotted will some what be easier then the slotless designs, mainly because you can just wind copper in a stator. Keep in mind that a really good motor requires a lot of engineering. Things like, how are you going to balance the rotor after you have it wrapped with Kevlar? How are you going to measure the Kv, Io, resistance and other numbers that people like to know about?

I've been trying to find a company to do my motors the way I want them done, but still haven't found the right place yet.