> The team intend to modify the existing \<thing>_case:nnn functions,
> renaming the last argument as 'F'. This reflects the fact that this
> final argument is used only when the test case (<thing>-dependent) is
> logically false, and follows the approach used elsewhere.
I think it's not a good decision. The argument specifier F implies for 
me that there is also a true part (T). So I would prefer to use 

>   At the same
> time, we intend to introduce \<thing>_case:nn, where there is no false
> branch (i.e. where 'do nothing' is the appropriate action).
I think this is a good decision.

I hope it's ok to post my thoughts here.

Best regards