With Swallow, enemy damage and hp is the only significant difference between the difficulties, food and Quen active shield mode doesn't matter much, and Sun and Stars is more a convenience. DM is the only difficulty where you have to parry and dodge with some consistency.
I've crafted and upgraded the Wolven Armor, it's pretty nice, it has higher level requirement than the other Witcher gear and good stats, and it looks like something Geralt could've worn in the prequels and a mix of Lambert and Eskil's armors, especially in the Enhanced and Mastercrafted variants. I've also done a few respecs, for now settling on a pure swords build with both Whirl and Rend, Fleet Footed, Razor Focus and Resolve. So I can use both fast attack, strong attack, whirl, rend, dodge, roll and parry to spice combat up a bit.