Anakin Skywalker is incredibly bright and quick. He catches on to things almost instantly, either through the force or his own intelligence. He puts together a protocol droid before he's even 12 years old, knows pod racers backwards and forwards, and even later, he shows the ability to think and act quickly (for example when chasing an attempted assassin on Coruscant).
But Vader doesn't seem to act as quickly. I know his suit is uncomfortable and forced him to change his whole light saber combat technique, but when I think over how Vader tried to handle the whole situation with capturing and converting Luke, now, I can't help but to wonder how a dark Anakin without the suit would have handled it.
It's hard to imagine someone brilliant enough to build a droid as a kid not having the insight and intelligence to modify a life support suit to make it more comfortable.
I'm not asking about why -- it's clear that Vader went through a major change by losing limbs and needing the suit. But Vader doesn't seem to act (not move, but to act or react) or think with the swiftness that Anakin had. It seems like his range and anger has significantly dulled his thinking.
Is Vader not as sharp as he was before he had the suit and is he not as quick-witted as Anakin was?