For more problems with the OOXML "open" standard: see Slashdot's Microsoft's OOXML Formulas Could Be Dangerous and the original article by Rob Weir, The Formula for Failure.
And perhaps of more significance, some real questions from FSF Europe to national standards bodies, perhaps lessons learned (or those which should be learned) from the OOXML standardization fiasco: Six Questions to national standardization bodies:
- Application Independence?
- Supporting pre-existing Open Standards?
- Backward compatibility for all vendors?
- Proprietary extensions?
- Dual Standards?
- Legally safe?