Patrick Durusau, Editor of the ODF specification(s) has offered another post in the vein of "can't we all just get along?" For all the discussion however, these documents from Mr. Durusau indicate a good path forward. This path is similar (the same) as what has been undertaken by DIN a while back. This seems to be a pretty reasonable approach; let's convene in an independent forum and discuss the real differences between Open XML and ODF (not just blinking text and spreadsheet formulas), and find out what interoperability really means.
Fundamentally this is a question of "Unification" vs. "Harmonization." My take on the issue is that people use these terms interchangeably, but I do not think this is the right way to conduct the discussion. "Unification" results in a THIRD format, not one single format. The Harmonization path (identifying the differences and finding ways to handle those) seems to be the area of convergence on the topic. I am a believer in this approach.
Rob Weir seems to have a different approach; it will be interesting to see who prevails within the ODF TC. While Rob and others may love to pull my quote about ODF functionality in our products, let me be clear: I do not believe it is feasible just to add features of one format to another. These formats are not subsets and supersets of each other, there are fundamental differences in text, table, graphic and style models, spreadsheets have a very different representation, and on and on and on. "Unification" points toward an argument about how product code bases will have to be re-written, and there are no winners in that discussion.
Suggesting that one can just copy / paste between these formats because they appear to be "90% similar" is an insincere / inadequate / uninformed attempt at understanding the issues that are involved.