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Out of these 3 former Jedi that have fallen to the dark side who the most redeemable in the publics eye? Who did the most vile things?

Dooku - ordered his sisters death along with his best friend.

Anakin - killed Younglings and many Jedi as well over the years.

Ben Solo - killed his father in cold blood and many others during his time with the dark side.

And do you think any of them even deserved to be redeemed?

Out of those three, Ben did the least vile things for sure.

Yeah, no Ben is the easy answer here. He never had time to do anything that was pure evil, and most of what he did he did to gain a sense of identity for himself. He was a lost and confused child, looking for purpose, so it makes sense that he'd be redeemed.
Dooku after him. He had some trouble with staying moral, but he wasn't immoral either. He had a sense of righteousness, and it could've led him to do great things if directed properly.
Vader is kind of a special case. If you go by some stories (like the movies alone), it would seem like he was just misguided and all it would take to get him back to being his old self again was feeling some love. But if you go by certain other stories, he realized that he was evil, and actively pushed himself further into that aspect of himself. He kept himself from being drawn to the light even after (in Legends) being tempted by his wife's love, his hatred of the empire, the hope that he could be happy, and (in canon) being shut down by Cylo and realizing that power was pain and happiness was the lack of enforced order. And that makes it seem like a miracle to me that he ever did redeem himself. If he hadn't, I would have said that it was impossible. The Emperor certainly thought so.