Perhaps, much to the chagrin of Microsoft detractors, the standardization process worked as intended
I bet if you compare this to other ISO standards in the past, the level of participation and review for Open XML is huge. We had a really large active working group in Ecma creating the original submission, and that momentum has continued to grow.
Once we move onto the next stage, the work will shift over to actual changes to the formats. Everyone will work together to help improve the spec according to the comments logged. I haven't seen any comments so far that should prove too challenging, but I haven't seen the final list yet. With the number of countries participating I wouldn't be surprised if we got somewhere in the neighborhood of 10,000 comments total. Many of these will be duplicates, but either way there will be a lot of comments to work though. I think that once we hit the ballot resolution meeting in February we'll see a significantly improved spec thanks to all the eyeballs reviewing it.