SPF is ten years old now. It would be helpful if you could give us a
list of other protocols that have had a similar issue with a TXT
record at the apex during the past decade.
I don't know of any (at least ones that are used in the global dns
namespace), and I would like to still not know of any in 2033.
SPF may be a lost cause, let's try and make that the only one.
Since we agree that the issue you're worried about has not arisen even
once in the past decade, could you clarify what problem needs to be
solved here?
R's,
John