I think you need to look at things like lunarian hax and CD regen outside the realm of linear powerscaling. To an extent.
You cannot bypass these powers. At least not easily. Hence defeating them isn’t necessarily about strength.
I get what you mean and I consider it a possibilty, but i think it's just very unlikelly to happen to be the case.
There will be a lot of HKs next to 4 (or 5) Gorosei member, that also have regen. And if they all have regen - unlikely it's only Gunko - you'd have to assume that all of them - around 14/15 characters - have to get defeated by (advanced?) CoC users of the protagonistic or anti WG side. I don't think it makes much sense, especially when some or most of the HKs might be high tiers.
There are only so much protagonistic CoC users that could realistically get a fight with them then.
In a battle against the Revs everybody besides Dragon would not even have to try for example.
If only Gunko has it and so there are only 5-6 regen people overall, that are also top tiers ability wise, I'd buy it.
But if all of them have it, I rather assume there's a trick to it. I also assume there's a trick to the lunarian power btw, so there's that.