There's nothing much to worry about here - yet.
1) The 'drag and drop' aspect applies to 2D sprite games only. There are MANY solutions out there already that provide this, including free ones (Game Maker) which are far more advanced.
The problem with 2D games built like this is you need to be a graphics genius to create something that anyone would actually want to play. If you can't draw for crap, or don't have a friend who can, you're a bit stuffed really.
2) To build a 3D game you need to be proficient in C# programming. I love C#, I think it's an incredible language to use, but notice how in the interview they never said once that it was good for 'beginners', because it just isn't. The whole XNA approach isn't.
So in short, you're back to where we are today - those who can already code well (in C# or C++) have the option of using XNA and paying $99 per year for doing so. Those who want to drag and drop a game together could also pay $99 a year to do so, and their game will still be no better than something made with Game Maker, except it won't run on any non 'XNA' PC.
Add to this that there was nothing shown in the video, or that I've downloaded so far, that couldn't be built in DBPro or Blitz3D, and more easily too.
For an example watch this video:
http://msdn.microsoft.com/directx/xna/videos/
Specifically watch Tutorial 1: Displaying a 3D Model on the Screen
It takes them 18 minutes (yes, 18 whole minutes) to teach you how to get a 3D object on-screen. That's all - it doesn't even do anything but rotate. The amount of code being used and generated by Visual Studio to perform just this basic task is incredible (hundreds of lines worth) - see around 9mins into it for an example. You need a good comprehensive understanding of real object orientated programming to do this.
I mean I know people here who could have written half a game in 18 minutes with DBPro.
I'm sorry, but they don't compare - different markets, different approaches. I honestly believe that DB and Blitz are perfectly safe from XNA for the time being. They'll have to really work on the 'ease' of making a game before it hits our market. If I was Torque on the other hand, who do rely on people knowing C++ to create their games, then yes I'd be more worried - but even Torque have a big ace up their sleeve with a well built, well tested engine + network code for you to plug into.
It *could* have been a real problem for us. Thankfully, it's nowhere near yet.
Cheers,
Rich
Heavy on the Magick