This is from the GDC's 2017 game development report. Where they sent surveys to over 4500 developers (not studio but individuals who range from hobbyists-to-profession developers. Which means at least 135 of those individuals are working on the unreleased system which is decent. It doesn't tell us much more than that.
I'm currently downloading the pdf right now to look at it.
Sales:
It seems that over half of those though it will definantly do more than the Wii U, 14% don't think it will do as well. And the rest don't care/know.
Core concept: (Mobile/Console Hybrid)
48% seem to think it may resonate with the public; 11% think the system will not resonate with the market. 19 percent think the system is the right product at the right time.
Other things:
It seems that the half generations that Microsoft/Sony are doing is being met with an overwhelmingly tepid respose. Only 18% thinks it is great for the industry and 5% think it is negtive. The rest don't care or are Neutral to it.
75% of developer think that VR is a sustainable market. The Vive has the biggest development share with 45% interest, Oculas with 30, PSVR, 29%, Hololense 24%.
