SharePoint and SharePoint Online Change Log
I'd like to see a change log to SharePoint On-Premises and SharePoint Online and of course the rest of the services/servers.
What I have in mind is a chronological, grouped by CU/PU/SP for on-premises versions and by date for the services, change log with all the changes to API's, PowerShell cmdlets and features. Very much like the Office Roadmap.
For instance in the July SharePoint CU we have a new addition to the cmdlets that allows us to bypass the search protocol handlers. In August we had a security update that change the EnableScript for Ribbon buttons added by apps etc etc.
Today this is almost impossible to track and will give the product/service a bad reputation. You have to either stumble upon it, read an obscure knowledge base article (which doesn't often state the changes anyways) or hope for someone to discover it and blog it.

Thank you for your input. Although we are are continuing to improve our documentation, we are also investigating the options for enabling this. However, there is unfortunately nothing on the immediate road map.