As for the application of Codex Arena's rule of weekly skill deck changes to Hero Battles, what's the ultimate benefit of it, if I understood you correctly, Motoko? Why limit skill choices available there to a lesser utility set? Considering the outlined terms of play are already implemented at the related outpost...
If I understood the environment and meta of HB correctly (I really never did put a large amount of time into it, not to get past rank 3 at least) - there were certain aspects of it that were buggy.
Now, it would probably enlighten me if someone could list all of the bugs... But I do recall shadow stepping and healing teams to play a huge part in the meta. I'd hope that Codex decks would limit those gimmicks and promote a variety of builds.