500 votesMichael commented
I really hope that the JSON project format sticks. This was a huge breath of fresh air and far easier to work with than the finicky XML mess with previous versions. XAML is NOT tool friendly, no XML format is "tool friendly", it takes a massive engineering effort to part every nuance of XML completely and properly.
Microsoft doesn't operate in a bubble anymore - they can't afford to ignore the rest of the ecosystem that is rapidly evolving around them.
I love the new Microsoft - .NET would quickly become irrelevant without Microsoft's new attitude, since it matters very little what runs on your server for web apps. The new JSON projects are just a small part of this and is extremely tool friendly - everything can parse from/serialize to JSON.
It's all fun and games until someone cuts themselves on an angle bracket.