Timeline was altered. NewDiana's like mid-meta in strength and toughness and speed (I think, it's hard to judge). She *just* learned to fly and gained the lasso. I don't think she has the cut-all tiara. She has bracers but they haven't demonstrated aegis effect and almost certainly don't have the lightning option. She's not nearly as experienced.
Basically, NewDiana is a different character. Slowly things are bleeding back and there's signs the timeline is trying to right itself, but she is not the herald-level, champion of pantheons powerhouse classic Diana is.
Classic Diana's one of the best people in the general level to go against BB, because her bracers do let her defend against the yell so well.
You gotta finish off Gail's run The last story has an invasion by some *badass* aliens called the Citizenry (as in, kills GLs and incorporates a watered down version of their tech into their infantry gear level badass), and not long before that one there was also a cool WW/Power Girl fight.
Maybe?
It's hard to say. Issues 601-4 were her fighting various threats and learning to fly, during which time we really don't know much about her personality other than broad strokes, and it's only in 605 that we learn how she's living, see her interact with non-enemies more, and so on.
It's not badly done, the fights are cool, but I was on the fence for awhile over whether I should care (because, after all, we don't know this Diana much. Also her starting as a non-flier then gaining flight seems to be a pretty irrelevant plot point, never does lack of flight hamper her, then she gets it? Yay, I guess?), and we still aren't far enough in the arc to tell whether it'll really be worth it.
In the long run, it may be worth it, but it has a slow start in short.
Yes, he's quite good in HtH too, is strong and tough, can manipulate energy, etc..
But the Voice is his big equalizer/trump card in most fights with stronger heralds, and removing it greatly reduces his ability to turn a battle around. Throw in that Diana's one of the best melee heralds around, and he's got a pretty poor matchup.
She can shut down his best range and will beat him in melee to boot.