Contrary to what you would expect from me, I actually think this is a good thing. Microsoft Office is the de facto standard. Being a de jure, official standard doesn't help OpenDocument if when you send an open document file to anyone they say that they can't open it. Ideally, Microsoft would have adopted OpenDocument but that wasn't to happen. The next best thing is for MS to adhere to their OOXML standard and alternative office suites support it. That Microsoft originated the standard doesn't mean that they will be the only one to benefit from it going forward. Just look at Sun and Java.
While I don't think the world loses with this move, OpenOffice (Sun in particular) and OASIS certainly took blows. OpenOffice can quickly recover by building in support for OOXML. The format should be easier to support than having to reverse engineer prior Microsoft formats. OASIS gets injured because it shows the limitation of de jure standard against a de facto standard.