Hmm, funny. For me, the separate settings per account were one of Sync's killer features. Maybe a straightforward, one button copy of settings between accounts could be nice, but I definitely wouldn't be happy to see this go hehe
I preferred having alternate themes per account. A theme export / import should be the way to go here. Maybe a global theme setting with per-profile overrides would be nice but seems like more work than it's worth. Themes are usually set once and forgotten once people are happy with them
I imagine it'd be annoying to have a ui to store this, ordeal with deleting accounts referenced... But maybe there should be a theme option in each profile to apply a customized global default or use another designated accounts custom theme? Or maybe I'm overthinking it and should just be a "copy from acct xyz" and apply to this new account and not worry about references to global defaults or other acct configs...