Re: As much as an MS fanboi that i am,
We have been there before. It's not exactly a new thing to digitally sign applications to stop them from being altered, but the problem is that such a mechanism immediately gets used as a revenue generator, thus shutting out all those applications you have been using for years but whose developers cannot afford the usually extortionate fee.
OSX has a similar mechanism (t's one of the reasons you need to register as a developer). That's not expensive (I think it's $99 or so), but ensures there is at least some track back to the developer.
In both cases, however, the question emerges how inhouse and contracted developments and customisations are approved - to me, that's the threat vector (next to ruthless exploitation of this lock down, because the real aim could be to kill off pesky competing software such as LibreOffice - which, by the way, does not have a dev registration for OSX either).
No, I'm not a fan of handing Microsoft any control.