I know what you said and I mentioned that even if it was 1s it would still be bad. Succor is a tier 1 spell and the equivalent of Helios/Medica, not Indom. Regarding clipping, you using 2 back to back isn't going to magically make it better. Aspected Helios and Medica 2 will still be better than using 2 for reasons I already stated. SCHs equivalent to a tier 2 spell like ASP H and M2 is Indom and you making it 300 potency is just going to push the burden onto them as the healing potency per damage potency isn't worth. Making it cost 2 Aetherflow stacks and keeping the healing the same would also be bad since it'd be 300 potency for a 500 heal which still wouldn't be worth.
I never compared Succor to Aspected Helios/Medica 2? Even then it doesn't matter because you SHOULD still compare Succor to Aspected Helios/Medica 2 since that's SCHs only GCD AoE heal and you NEVER use Medica/Helios in an optimized environment EVER. This means WHM/AST AoE heals only consist of ASP H/M2. It doesn't matter that their HoTs when it only takes 12 seconds for it to outvalue Succor especially that there is hardly any situation in the game where you would utilize succor > ASP H/M2. Succor is 375p /hGCD for 230p damage while ASP H is 660p/hGCD for 220p damage and Medica 2 which is 700p/hGCD for 250p damage. Just because it takes time for it to outvalue a Succor doesn't matter since most damage in this game doesn't happen within 10 seconds of each other and actually statistically most damage happens 30-60s apart from each other. The average distance between AoE damage in O9 is 40 seconds, same for O10 and O11. 12 is actually worse because there is small burst damage every few minutes and no damage for 60+ seconds.
I know that oGCD usage is the problem. I've stated in this thread before that Earthly Star and Collective are the sole reason you can use 0 indoms in 9-11 without hurting your cohealers damage. Ironically enough if you make Indom cost 2 Aetherflow stacks or change it to 300 potency you're indirectly nerfing WHM as well since it would be even more of a struggle to optimize healing with them them due to their lack of efficient healing tools. Which would make AST+SCH comps even stronger.