I have yet to see an actual burned out controller, they rarely do that. When the range of motion is not what the ECM expects it sets a DTC and goes to a default position instead of trying to set itself. Have seen several failures where the turbo was the problem, once the mechanical issue was fixed and the actuator reset done they worked fine.
EGR circulated back thru the intake can and will cause build up in the turbo because it makes the combustion event stoich richer on top of the stoich rich programming. Raise the cylinder temps by removing the EGR and that propagates to the turbo and DP leaving more soot to collect in the rest of the exhaust system as the exhaust cools.
I don't see how removing the EGR can raise the cylinder temps in and of itself.
Since the recirculated exhaust gas pollutes the combustion mixture and causes it to be less efficient (exhaust gases displacing oxygen doesn't sound like a winner to me), it would seem that all you'd have to do is send less fuel to the chamber in order to keep the combustion chamber cooler (lift foot off of pedal).
IOW, I see the exhaust gases being sent back to the combustion chamber as a net negative; making the combustion event far less efficient and sending more soot and ash through the exhaust system.
'Work' generates heat. Heat is work, energy is heat, heat is energy. Less work, less heat, lousy combustion, less heat, less work. Better combustion efficiency, more work, more heat, more efficiency.
simple physics
But that's just me and I'm often wrong about things like this. I just don't see how dumping exhaust gases into a combustion chamber is a good thing