A number of less optimistic views are beginning to form on MS's decision regarding support of ODF, PDF and XPS in its Office 2007. Probably amongst the most notable are the Register  , ODF Aliance, Groklaw and the European Commission – these are ranging from conservatively cautious to outright pessimistic. The smallest of all worries posed was in which way MS will implement the ODF support in its Office package – will it be as easily accessible as Microsoft's own OOXML (or deprecated binary format) or will the user have difficulties finding the option. According to the development screenshot on Doug Mahugh's blog and other MS info this should not be a problem. But I think we already learnt that you cannot judge the day before the evening, when it comes to Microsoft's promisses.
There is also the problem on how well the implementation of ODF (and PDF) will be made. Even assuming that MS will implement all of the ODF in reasonable quality – which already is a huge assumption, since already the by MS started third-party project ODF-Converter shows a lot issues that are (nearly) impossible to be supported equally in both OOXML and ODF – they said that in its MS Office 2007 SP 2 (which is due in 2009) will include ODF 1.1, while ODF 1.2 is already being developed and many other office suites are aiming to implement the 1.2 specifications as soon as possible.
The probably biggest – yet not so loud – problem is the (either well planned or sloppily neglected) threat by the RAND license terms and Microsoft's OSP which SFLC declared incompatible with GPL. The core of the problem is that OOXML (and some other "open" stuff by MS) is covered by MS OSP which read carefully can be interpreted in a way that it does not permit usage in FOSS – even more: it is incompatible with GPL. This in turn would sound very nice on paper – possibly trying to convince the EC, governments and other big customers that MS did its best to comply – but in reality not only pose no protection for FOSS that would like to use OOXML specifications under the OSP, but even prohibit it from using OOXML. If this is by cruel intention or by sad chance is debatable, but whatever the reason it is definitely a matter to keep an eye on.
Also the EC points out in the above linked press release that [it] would welcome any step that Microsoft took towards genuine interoperability, more consumer choice and less vendor lock-in. In its ongoing antitrust investigation concerning interoperability with Microsoft Office, the Commission will investigate whether the announced support of ODF (OpenDocument format) in Office leads to better interoperability and allows consumers to process and exchange their documents with the software product of their choice. Which hopefully means that pretty (buzz)words will not blind the EC and that someone will look over and be able to punish any potential antitrust moves that MS could make with this action.
My personal view on the whole matter is that it seems some people who work for Microsoft already get the idea that the networking effect and vendor lock-in by forcing their users to stick with MS products because they are planned to be incompatible with competing solutions is not the way to go. The question remains if there is a) enough people in MS that think this way and b) if they are on the right positions. Sadly I have my doubts, but I am preserving a small spark of hope that a shift in the heads of the heads of MS has happened. The thing that scares me the most is MS trying to make ODF and OOXML standards more compatible on the OASIS and ISO/IEC level – this can either go in a brilliant direction or terribly horribly awry! On one hand there is the possibility to finally have two (one more, one less) open standards, that could theoretically be supported by all of office suites out there almost equally and the users could choose the applications they want to use by their features and usability. But on the other hand it is also not beyond imagination that Microsoft could (ab)use its involvement in these standard bodies to either diminish the value of ODF (and PDF) by bad choices and hence make OOXML (and possibly XPS) in comparison seem better or (more likely) make them all more compatible with MS Office to the extend that it would be a lot harder (or even impossible or illegal) to implement them perfectly in other office suites.