Form is indefinable. That was the problem the "anti-rave" legislation faced. You would replace a definition that you would criticise as inexact (although I think you are wrong) with one inherently indefinite.

The function of a definition is to enable determination of what falls within it and what without. Your problem with that is?

It also of course helps if the definition correctlyspecifies the subjectmatter, and I can see no fundamental defect in parameters addressed by the 1954 definition. They might be capable of more precision - but actually you don't seem to want that, do you?

I am reminded of the argument between Manfred Mann and Sonny Boy Williamson, about how many bars there were in a 12-bar blues. To MM (all trained musos) the answer was "12"! To SBW it was "as many as I want".