.NET is actually a joy to work with. Being able to write apps in C# for OS X has been a dream for a lot of developers. It's a very lovely language and supporting framework.
I don't mind Objective-C. I like Swift (a lot). Though being able to use C# on OS X and have first-party support and tools from Microsoft would make me a very happy camper.
Great way to churn out second-rate programs on the Mac!
You're depending on Microsoft for the interface. Since when is that a good idea?