In the Office document format war there is a lot of critique on the OOXML format specifications especially now that Ecma has submitted the format for ISO fasttracking.
It seems like many people do not understand the purpose of ISO fasttracking standardization. The fasttracking method is a standardization process to easily guide existing industry standards into an ISO standard. It is not meant for creating a new standard from scratch but to get existing technology which has a broad basis into ISO.
ISO standards are meant to be used and ISO has a pragmatic policy that it needs to provide standards that are have a market requirement. See also this post by Rick Jeliffe on ISO standards: http://www.oreillynet.com/xml/blog/2007/02/what_is_a_standard_at_iso_1.html
OOXML is a standard originating in the MS Office 2003 XML formats, SpreadsheetML, WordprocessingML and PresentationML, formats which first showed in the august 2000 Office XP beta. This means that the formats are already well established in describing the features of Office documents. Important differences to those old formats in OOXML are the use of the Open Packaging Convention and the Markup Compatibility and Extensibility and putting embedded (binary) files in as separate files in the package and remove the binary content from the XML files. Also the OOXML specs old markup languages have been augmented to take tons of examples and a good structuring for implementation by using parent and child elements being defined everywhere. And finally the VML vector language format is being replaced by the new DrawingML format (although VML is kept in the spec for compatibility with the MS Office 2003 XML formats that used VML).
This is an example of why the format is not perfect. It carries with it the burden of backwards compatibility and the amount of extensive features being used in MS Office. But it also combines this with a spec that has a lot of possible issues in it already dealt with. It would be very hard to stamp out a completely new format that could be used by an Office suite like MS Office. Certainly a spec like ODF which is pretty good would not suffice as it leaves a lot of things still undefined or up to implementation. ODF is improving this by improving it's specs and extending them in newer versions and also by trying to create a set of reference documents to further define it's implementations. Still it is has proved very hard to get an implementation that could implement the entire ODF spec even 20 months after it has been standardized by OASIS even without looking at formula's. http://testsuite.opendocumentfellowship.org/summary.html . This shows that implementing a complex Office spec even when you already have a full Office suite as a basis is a process that can takes years.
This is basically what Microsoft has done with it's Office format. It has taken more than 6 years to put it's Office suite towards a full XML implementation that is also backwards compatible with it's billions of legacy documents. Then it has opened up this format for everyone to use by standardizing it trough Ecma. It does carry some scars from that development but it also is a spec that is in full use with many of it's key markup elements like the formula's having proven themselves over a longer period of time. In ISO fasttracking that is important as it show that the format has pedigree in the real world and that it has use in the market of today.
OOXML is a format that has a foundation in the market and has most of it's features proven in the last 6 years. It does not have perfection but then again neither has it's competitor that is still being worked upon. For the ISO national bodies that market foundation and proven track record are important aspects for approving this format. The Ecma standard does have several newer less proven elements for sure, which have to be considered in this process, but as of now, those new elements are the elements that seem to be least criticised which also show that the development of the format is improving toward the future.
The ISO fasttracking process does not need perfection but it relies on a standard that is based on existing technology that will be massivly used in the future. This is exactly what OOXML will prove to be and I think that is why ISO will approve this standard as an ISO standard despite the protests from the open source community and MS competitors.