I don't think there's any point turning this in to a Microsoft rant/debate. That's been done to death a million times already.
The main problem with DirectX in Construct is actually technical. That darn D3DX update causes a lot of people headaches, especially due to not-reading-error-messages syndrome. Portability isn't the big deal it might seem, since using OpenGL probably won't help with porting to XBox, or web formats. The fact it's easier to program for is also nice for us, but I doubt anyone using Construct really cares about that. But we have decided to go with OpenGL for C2 anyway.