There's already talks about MS doing something similar with Windows 10. Giving it away for free and then once it has a large user base start making changes. See it's changes like that that create paranoia in people about a company. It's a trust issue.
The moment they try to charge any sort of subscription for Windows 10 after saying "it's free, forever" is the moment they'll simply shoot Windows in the head and give an immense boost to OS X, ChromeOS (which I am betting by then will be unified with Android, despite Google's current denial), Linux and Pirated versions of Windows.
I have a Windows 7 and Windows 8 disk. One of the advantages Windows 10 offered me that Windows 7 didn't was the integration with OneDrive. But since OneDrive will become - come 2016 and unless they reverse this - useless, the appeal of Windows 10 to me is basically gone. If they try to charge me for it I'll simply pick up the Windows 7 disk, format the PC and go back to Windows 7.
As for cloud solutions, I'm currently moving everything to Google Drive (which, what do you know, just offered me 100GB extra for 2 years when I opened their Android app which I had never done since moving to Android because I kept using OneDrive) and I'll just get myself a WD My Cloud, set up a personal cloud and be done with it.
And honestly, even if Microsoft reverses these decisions, my confidence is already broken. I won't use OneDrive as my main cloud solution ever again because I simply don't trust Microsoft anymore to upheld their part of the bargain. Now they say Office 365 users will still get 1TB...but who's to tell me that in 6 months they won't change their minds and reduce that to 500GB?