Thanks for the facts, though I'm still super, super skeptical of the "Snyder wanted to use Cass, but had to create Harper" claim, since I've been searching for it for literally four years, and can't find a single printed source for it.
Adam Beechen said in an interview just before Steph took the Batgirl cowl that Pete Tomasi was actually not his first editor on Robin, I believe, so it's difficult to really tell who dictated Evil Cass. Berganza did have a harassment scandal, but he's still group editor of the Superman office, though DC pretty severely restricted him and required him to have serious psychological treatment.
DC in general has trolled fans of Steph and Cass at cons.
We can definitely thank Snyder and Tynion for bringing Steph and Cass back. Both Eternals were Tynion's babies, and Snyder lent his weight to the effort to make sure it got past editorial resistance.
I also love Gates of Gotham, but wouldn't mind a bit more Cass focus.