I think it would be a fairly safe bet to say that the next xbox will have heating and heat/cool cycles tested far beyond what is normal, and the products won't have any issues with heat
One could've said the same back before the 360 was launched too. You just never know. At least speculation of hardware quality is a valid concern, seeing with what happened with the 360 fiasco. I'd still be a bit skeptical myself, seeing how they released the Surface Pro which is quite warm when just sitting idle.
I'm certainly no early adopter though when it comes to hardware.