on practicing improvisation

Improvising over chord changes is very difficult at best.
so what's a good way to approach this incredibly complex topic?
i know you want to get these lydian arpeggios handled, and practice diminished patterns as well as bebop lines and... but didn't you want to try this concept called target note improvisations? and oh wow you almost forget to transpose Autumn leaves to 9 other keys and...

enough!
Let me introduce you to one my favourite topics here.
it's called "focus on one thing at once".

center yourself, forget anything else you could possibly practice and dedicate yourself to doing one thing at a time only instead of getting lost in the universe of jazz guitar over and over again.
this is quite the opposite approach of what Mick Goodrick teaches in his book "The advancing guitarist". It's a great book, with the purpose of increasing the students perception on how many different learning fields there actually are. it's goal is to make the students inner voice say "Gee, i really got some things to do. i should start!"
The downside of this concept is that a lot of students end up being overwhelmed when trying to practice everything simultaniously.
So in fact my concept could also be called "antagonizing Mick Goodrick"

Stop in your tracks for a moment and ask yourself:
"What do I want to be able to play?"
"How do I get there?"
and most importantly "How can I downsize this exercise even more, so that I actually benefit from it."

Dedicate an hour of practice not on improvisation over changes and not on arpeggios, but rather on improvising with only four notes at a time over a specific chord type in one position.
Only when your brain is not overwhelmed with new information are you truly going to learn.

for example practice:
"Creating three new cool patterns over a Gminor7 in the first position using the notes Bb, D, E and A exclusively."

Do this straight for two hours. And don't interrupt the procedure by thinking

"Ok, cool, but what other notes would fit in?"
"And does this work on another chord?"
"How about four notes from the mixolydian #11 scale?"
"And should I or should I not transcribe Kurt Rosenwinkel's solo over this tune zhivago?"

Keep at it, and don't let anything distract you. Do it for two hours!
As soon as your mind starts asking these questions, stop!
Ask yourself "what was the plan?" and then return to it at once.

you'll be amazed what difference this is going to make if you follow through with this for a few months.
if you want to go back to doing it all at once, fine.
but in five years, do not tell me i didn't warn you ;)