Susan, I couldn't agree more. I have always allowed my ear to do the right thing. 45 years after I began improvising, I am still learning the theory of why some things work musically. For some follks, though, it needs to be a little more structured until they sort of get the formula in their heads.

I played a gig on St Paddy's with a group of "Irish style " musicians. Technically very good musicians, a concert flautist, harpist, etc but they read everything we did. It was the most disappointing music I have ever done, albiet technically played like it read off the page. Given a chance I would always prefer music from the heart!