Microsoft have previously acknowledged that the growth of the Windows Marketplace has resulted in some scaling issues, and these changes have a direct impact on the resources required to run the Marketplace. I suspect that Microsoft have taken a look at all the usage data and how much resources are being used and decided the best course of action in terms of what is available.
Of course, there's going to be some heated discussion from people online (start with the comments on the official blog post...) who happen to like buying and downloading directly from Zune Desktop, but the big issue is the communication of the changes. Loading up the Zune PC Suite this morning, I had a pop up dialog that told me things had changed - but not what had changed, or a link to more information. When removing features, I'd expect much better communication to the user.
It would also be nice to prepare the customer for a loss of a feature. This is being done with the non-Mango Marketplace access, but not the Zune PC Suite. Let's hope that everyone has the time and ability to update their handset to Mango in time.
Were these necessary actions? Probably, but one thing's clear: when the jump to Windows Phone 8 happens on the handset, Microsoft need to be a lot clearer than they have been today.