IMO, I think its a security problem. People run diffs on the updates and use the detailed bug fixes to uncover exploits faster than most can patch. It could also be MS ending the era of "admin approved updates". Google started it and now MS competes with Google and even Apple in the the School market so it makes sense in a way.
It's clear they are boiling the frog prepping for Windows as a service. And on a SaaS model you have to take that control away to keep costs down. Obfuscating the full extent of the changes is just part of "making sure you have the latest and greatest"and why many apps for example have stopped including actual release notes in app stores.
Scary release notes and the opportunity for users to say no are bad for business.
