Provide free technical preview sandbox
It often proves to be difficult and costly to maintain a prod environment, and a lab environment on top of that. It is not becoming almost essential to have a technical preview environment, but in corporate culture you cant just stand up another server with a domain without significant red tape and support costs.
It would be awesome if Microsoft would provide cloud hosted TP environments like they had for SCCM 2012 in the virtual labs. They need only last 2-3 months, and then just blow them away to create a new one when the new TP is released.
I understand it may introduce slight cost increases to Microsoft, but I'd venture it would highly increase participation and testing of the TP builds.