Moving C6 to the other side of the shunt allows the shunt to see the capacitor's discharge current but nothing can be done about it anyway.
I mainly set out to solve the problem that many PSUs must have, where the short circuit current is unlimited for some time. My Agilent U8002A will supply the full set voltage into a sub ohm load, tens of amps, for 100us before the CC loop begins to respond.
Something can be done, decrease size of C6 to decrease current dump.
Increase control speed to reduce 100us.
The more you reduce R1 the faster you can change.
The more current you can pump in/out Q2 gate the faster you can change.
If you have control then you can add functions.
The faster you can make circuit respond the less time output is uncontrolled.
Faster also reduces overshoot.
Think about it. you can drive a hot rod on the street with proper control. A bad driver will end up in a tree, while a good driver has power to get out of way.
The difference is how good is the control.
One of the big problems for a power supply is the unknown load.
I have seen power supplies that add a scaled internal voltage load & a scaled internal current load not effected by output load to get better control.
Need to keep in mind total result & how each part effects local area & total.
for example
C3 has two effects, removes noise & slows changes.
A cap across R20 does same for output.
A cap across R21 adds output noise & speeds changes.
There will be matching places for CC side.
Using both an AC divider.
You can use separate dividers and mix two at input to op amp.
Remember that when you add a cap that the effect is different at DC then at high frequency.
Try to have few caps and really think about it before adding one.
Right now you are running op amps open loop with total circuit controlling gain. You have option of some local resistor feedback which would slow all changes.
Note that you can use many feed back paths. Op amps are commonly used to combine two audio sources for example.
Might think of three inputs to op amp, scaled output, reference input and local feedback that gets canceled or over ridden to keep output off rails.
Old timers often used positive & negative feedback.
If you have 1v positive feedback and 1v negative feedback. A set of matching resistors in series = 0 feedback.
Remember that mode change is by conduction curve of diodes. Diodes have capacitance.
Diodes only pull one way. Watch for difference in over shoot vs under shoot.
Your LED's are adding error to output that is different between low and high. I would think of using a quad comparator for leds.
When thinking of a change, really look at the many ways to accomplish same thing.