Hi Tuomo,
I think the method you explained both in seminar and in Advanced improvisation course is extraordinary and can improve significantly the improvisation skills.
Indeed, my improvisation always has the defect to resemble like “random notes” played over chord changes, and instead the method forces to give a kind of repetitively.
To be honest, also professional improviser often give the impression of continuous changes in the improvisation, that becomes difficult to follow.
Previously I learned a different approach to theme improvisation from Gary Burton course: he takes a theme, very short, and play it over chord changes:

1. Changing the rhythm
2. Inverting
3. Playing only a part
4. Changing the interval in it
He does not try to fit the theme over cadence 2-5-1: this method is good but remains the impression that the improvisation changes

My questions are:

1. Where do you use to find the themes? From the improvisation of musicians? and witch musicians you think are better to find interesting themes?
2. Can you share some more themes you worked on?
3. Should the theme somehow resemble the melody of the standard?
4. What do you advice best to play between one cadence and the other?
5. How to avoid on the opposite of a random improvisation and annoying and too repetitively improvisation
Would be great for me if you could arrange a seminar dedicated to the previous questions.

Thank you so much
Alessandro