Improvisation is a complex matter, and often a contentious one: some degree of musical freedom is usually identified with it, to the extent that freedom is sometimes regarded as its defining characteristic, its essence, or indeed as the thing itself. Thus some more partisan free improvisers would not really regard formulaic improvisation (improvisation within closely bounded harmonic and rhythmic parameters) as improvisation at all. I’ve never had much time for debates that centre on the definitions of musical styles or characteristics, but I guess that if you’ve staked your career and practice on a particular ideology of creative freedom the stakes might look higher than they do to me. Personally I think there are other parameters of improvisation…