Over its short lifetime, Windows 10 has already received a number of cumulative updates that combine security fixes with some number of non-security bug fixes and perhaps even the occasional new feature. To be honest, we're not entirely sure what the cumulative updates contain, and there's a simple reason for that: while security updates do receive official documentation and enumeration, the non-security stuff is not described by Microsoft at all. When asked about this last month, Microsoft affirmed that it has no plans to tell anyone what's in the updates.
This is frustrating. If an organization is holding back on deploying Windows 10 because of bugs it has experienced, it would be useful to know if those bugs have been addressed. Even when Windows 10 has been deployed, it's helpful to know if a given build is supposed to fix a particular bug, as it can aid diagnosis of issues and make clear what's supposed to be happening, even if something isn't working correctly. Any user-visible functional changes make this even more important; if the operating system is going to change, people should be given some idea of what to expect.
At a time that Microsoft should be striving to build confidence in "Windows as a service" and its new update and release model, its peculiar reluctance to explain what goes into each update seems more likely to drive IT departments into using the infrequently updated Long Term Servicing Branch instead of the mainline Windows release. Microsoft's guidance is that LTSB should be used only on those mission critical systems that absolutely cannot tolerate anything more than security fixes, but if the company is going to keep people in the dark about what they're installing with each update, plumping for LTSB may well be the rational choice for the concerned administrator.