In my experience, the best way to learn solo over changes is to approach changes from every possible angle. A lot of the scaler sequences are what Todd Johnson speaks of in his "Ask a Pro" Forum.
I generally have students begin this stuff by:
1- learning all of their modes
2- Learn all of the practical chord shapes for every type of chord
3- work through a tune every week (or 2) and do the following
4- PLay through the tune at a number of different tempos and:
- Play every arpeggio in time in 1st inversion, then 2nd, 3rd
- PLay through the chords (in all inversions if you really want to go for it)
- Practice walking through the tune
5 - NOW work on soloing and you'll see how all of the work you've done pays off... You'll see each chord from any number of angles (not just from the root) and every time you play off of a chord and it's inversions, you may notice ways to extend your line off the extensions from the next chord, leading to another inversion of the next chord, etc...
the key is to then introduce melodic and rhythmic phrasing so it doesn't sound like....exercises and scales.
You can also try something like soloing in groups of 3 or 4 note phrases only using the 9 and 7 of each chord, for example.
Stuff like that can really open your ears (by limiting your note choices, you force yourself to really think about the chords and the way you phrase things).
and, of course, transcribe! But, don't just figure out the notes and write them down, look and the scaler patterns in relation to the chords, look at the shapes of the phrases, look at the melodic patterns, etc...
Try and get inside the head of the soloist you are transcribing.
Jazz is hard. You also have to listen to a lot of jazz to really internalize the feel. I've never been a great straight ahead soloist because it's not my thing, and that's what it is. BUT all of that work has really paid off in every other way possible (and I can get through a tune pretty darn well, it's just not an authentic sound I create to my ears).
This is the real meat-and-potatoes of it all. Do this stuff and your harmonic and soloistic world will inevitably open further in some way.
Hope someone gets something out of that!
