I liked Aquatic Bane but I think the lack of clarity is what hurt it. Personally, I'd call it "Waterbirth Bane" or such and focus it more on Dagannoth, Wallaski, and Rock Crabs (the three Waterbirth creatures), which also would mean it would be useful on training on Rock Crabs too.
Even that requires prior knowledge to understand which monsters it would work on but I suppose it’s an improvement. I think there was some contention over armours having the effects usually given to jewellery as well, although not 100% sure on how many thought that. It would also be confusing that it works on dagannoths on waterbirth, but what about the ones under the lighthouse? Needs some thought, for sure.