Nice bit of camouflage..
In a move that resembles Google's push for encryption, Microsoft's blocking of Flash is mere distraction. It's like banning fat people from the higher part of the tower of Pisa; it does nothing to address the fundamental security problems this platform has to cope with*.
Worse, as they will soon have people on subscription, the last incentive disappears to ever fix it.
Too little, too late, too futile.
(*) Traditionalists can use the deckchairs & Titanic analogy.