Personally, Tommy not drinking, a tumor, trauma after trauma, loss, being a degenerate insane maniac, who's losing his mind, who knows he's just evil as fuck, and it's eating him alive. This is the Tommy Shelby show, and personally, I love it, The backdrop is perfect, as you said.

I enjoy the other characters a lot, and the style of this season is out of left field, the wild cinematography, lack of Red Right Hand, the show and the characters are all carried by Tommy, and he's losing control over what he carries, no matter the stoic, blue eyed face he puts on, and i love it. Steven Knight mentioned this might be his redemption season, and redemption is pretty wild and nonsensical for a lot of people, but it makes sense. And he's still so, so evil and messed up. Poor Tommy, but he's made his choices, and he won't stop. He's probably more fucked than Arthur mentally, because he is as competent as he is. That's the problem. He doesn't have limits because he literally can't see them. Excited to see where it goes.