Can new MS Office format replace correctly old MS Office format?

A few friends of mine are concerned that the new MS Office format OOXML (discutably standardized as ISO/IEC 29500) might not replace correctly the previous one. Should they change their organizations' practices to the new OOXML or stay put with the old .doc, .xls, .ppt and so forth?

One assumption was that Microsoft would write the file format to allow for a correct representation of all the previous content. This was in their interest because they then could say to their customers that the transition would be seamless.

However they were criticized for including say "direct representation of old formats" rather than "complete representation" of the same data. Or more simply, they made OOXML represent the mechanisms of the old .doc and .xls, rather than provide something to represent the same information in a unique, coherent new architecture. This means that the OOXML format inherits a lot of the complexity and some bugz and patchz of the previous formats. But it's not my point today.

My point is that when doing this, they forgot things (due to the high complexity of the previous formats I suppose), which made a subcomitee of the ISO say that it is "impossible to fully represent some of the corpus of existing documents in [OOXML] ISO/IEC 29500". So to the questions of my friends about switching to OOXML, my answer is: wait and see.

If there is one thing I am sure about, it's that we have a lot to see from MS competitors: IBM has its own branch of office suite linked to OpenOffice.org, Oracle has just bought Sun's OpenOffice.org and Google will not let go of online edition.

If there is one thing I am convinced about, it's that OOXML is not a mandatory shift so far.