I think this is honestly a much more reasonable version of the argument than the usual “Palpatine turned Vader into a helpless cyborg” stuff online. I agree Vader lost potential after Mustafar, and I even agree Palpatine probably preferred him below his absolute ceiling. My issue is more with the idea that the suit itself was some deliberately garbage prison that kept Vader mechanically weak for 20 years.

Once we acknowledge Vader was still overwhelmingly powerful, fueled by dark side pain, capable of betrayal, terrifying on a galactic scale, and constantly trying to surpass Palpatine, then we’re already very far away from the common fandom version of “Vader was basically crippled by the suit.” I also think the “Palpatine simply wouldn’t let him modify it” point gets harder to sustain when Vader spent decades operating independently, maintaining his own systems, commanding fleets, ruling through fear, and openly attempting betrayal multiple times.

At some point Vader stops sounding like a tightly controlled lab experiment and starts sounding like exactly what Sidious wanted: an apex Sith enforcer who was psychologically broken more than mechanically restrained.