Furthermore, nobody except maybe vultur really seems to believe that the problems with ACaEBG are anything but real.
Oh, I'd agree that *if* it's treated as a -3 refresh cost power when independent from the Sword, it's a problem. I just don't think that's a necessary conclusion from the Sword writeup, since the Holy + steel Sword fills so many common Catches even before ACAEBG.
Similar stuff, yes, would happen if somebody with Supernatural Strength gets hold of a Sword of the Cross (I think that'd be quite a stretch settingwise except in really unusual circumstances like the final battle of Changes, but...) Personally, I think the Swords have clear enough roles and linkage to the Knights that there's kind of an implicit warning sign if you want to give one to a Scion of Hercules or whatever, but maybe not.
@vultur: It's actually less powerful with Claws than with the Sword, since the Sword is probably weapon 3 and Claws are only weapon 2.
"Beating a Catch" is stronger, yes. But ACAEBG, as such, not so sure - since a hypothetical SotC
without ACAEBG is already going to beat a huge proportion of Catches in the setting, being both holy and steel. Demons, Blampires, Rampires, fae, Denarians (except Nic), ghouls...
The problem is that a Sword + Strength/a stunt makes for attacks that absolutely nothing can survive a hit from without consequences. Armour doesn't work, extra stress boxes don't work, Immunity doesn't work, nothing works.
Because of the above, however, how many things does that affect that a non-ACAEBG-bearing steel, holy item wouldn't? White Court Vampires (who generally lack Toughness anyway) and the real heavyweights (HWWB-style Outsiders, Nic, Dragons, etc.) ... anything else?
So it's really only that powerful if you regularly fight the very big powers (and not even all of those, even the highest-end Faeries still are vulnerable to iron, the Black Court Elders had most of the same weaknesses - though less to sunlight, etc.) So yes, I can see why it'd be worst in a really high-Refresh game.
Some sort of cost-scaling mechanism might balance out the power, though, just as you suggest. Perhaps you could make something like that?
Possibly -3 in situations like the Sword where its use would be fairly rare because most common Catches would already be covered; -4 in a situation such as just-Holy (a being with Holy Touch maybe) or on a non-Holy steel weapon; maybe -5 totally on its own?
Something like:
All Creatures Are Equal Before God [-5].
You can make attacks so infused with holy power that they pierce the mightiest defenses.
Musts: This power is generally found on an appropriate Item of Power (in the canon Dresdenverse, this means the Swords of the Cross, though in your campaign others may exist). To take this power directly (without an Item), a character must have a High Concept denoting a 'heavyweight' power of the Light, such as AVENGING ANGEL. It's possible that in your particular setting certain other beings or mythoi might possess or grant equivalent powers, though so far there's no evidence of that in the Dresdenverse as we know it; in such a case, an appropriate High Concept is still required. (For example, Surtur's apocalyptic flaming sword might well be capable of destroying its target through any possible defense.)
Benefit: The character may spend a fate point (in the case of an Item of Power, when used in accordance with the Item's purpose) to negate the supernatural defenses (Recovery/Toughness powers and Physical Immunity - as if the character had satisfied the Catch), as well as mundane Armor*, of one opponent for the scene. Extra stress boxes without a Catch such as those provided by Hulking Size, and extra consequence slots from skills or stunts, are unaffected.
Cost: Normally, this power costs -5 Refresh. When applied to an item that will already satisfy a very common Catch (such as a holy item, or an iron/steel item), or a creature with equivalent powers (such as Holy Touch), its cost is reduced to -4. When applied to an item that will satisfy several common Catches (such as an item that is both holy and iron/steel), its cost drops to -3.
*Maybe this should go away; I'm not sure it's actually necessary for the Swords to do what they should do. What do you think?