First SQL Server for Linux from a few weeks ago, now Bash for Windows 10 from Microsft Build this morning. Really unexpected!
I’m not a developer by any stretch of the imagination, but with the little I do, I think Bash would be useful. Even though Cygwin is good, something baked into the OS just feels right. (And it befuddles me why certain really basic packages are not installed by default in Cygwin; I guess I’m not power user enough to appreciate the customisability).
To be honest, I like developing in Windows. I feel its more manageable than Linux and less restrictive than OS X for development.