re: Score another point for XMLA and MDX

I think you're absolutely right, it's compatibility with Excel pivot tables that's driving this. But that only means that everyone's XMLA is compatible where it matters for Excel, and that's not all XMLA. I still think it would be great to see the XMLA council resurrected for the reasons I gave in the blog post you link to - it would make the client tools vendors lives much easier, and it would mean consultants like me and developers would be able to move between platforms more easily without having to remember so many platform-specific tricks and quirks.