Add new functionality now or later?
One thing we had to think about in TC45 when dealing with the national body comments was how to deal with requests for additional features or functionality. It's important to make sure at this stage to only fix issues in existing functionalities and that you don't put things into a standard that haven't been properly vetted.
For example, while I was surprised that ODF didn't have formulas in the first version of their specification even though spreadsheet formulas had already been so widely used in the industry, it wasn't as big of a deal that they don't have rich ink (handwriting) functionality as that's a bit newer in terms of office document integration and could probably use a bit more thinking in the ODF camp.
There's a great quote from Charles Antony Richard Hoare in his book "Essays in computing science":
When any new language design project is nearing completion, there is always a mad rush to get new features added before standardization. The rush is mad indeed, because it leads into a trap from which there is no escape. A feature which is omitted can always be added later, when its design and its implications are well understood.
This is why in TC45, we made changes where we felt we had the appropriate fixes and extensions to existing functionalities that were requested by National Bodies. We did this where we felt we had adequate time to think through the design. In other cases though, we had to push back and say that the suggestion was valid, but it was more appropriate to handle in future maintenance. Of course the final decision has to be made by the national bodies during the BRM.