Primordis

I like this idea, but only if it offers decent set bonuses. Most people who would actually care about the healing part of powers like siphon life probably already have spiritual alpha or similar, and if you throw in one regular heal IO +5 with that, you're already at ~80% heal. Like you said, no one is going to slot consume for damage, just like no one is going to slot dark regeneration for damage, so this only applies to a handful of powers like siphon life, life drain and radiation siphon. I'm not sure about the chance for hp either, I think something like a chance for stun/fear/sleep would be more useful and more thematically appropriate. What I think would sell this idea is really just the set bonuses alone. But that's an issue that's way more broad than just this specific application. Set bonuses as a whole really need to be more diverse. And this line of thinking should also be proliferated to accurate tohit debuff, which is arguably more useful for a dark melee/ranged character. That one is harder to implement effectively but is very helpful late game. My scrapper uses diamagnetic 100% chance for tohit debuff while using DM, and after a full attack chain I can bring a +4 boss' chance to hit down to about 15-20%. So I can see your idea definitely being useful for theme or for people who like strong heals, but at the same time you could just get a incarnate alpha with some kind of heal component and call it good. The difference between a 33% heal and a 95% heal on a siphon power isn't that big of a deal, because it was never going to be a large heal to begin with. It would be way more useful if they buffed the actual base heal amount of the attack. This would make for a good QoL improvement so you could use siphon powers for healing minor/moderate dmg and saving yourself time, allowing you to continue your attack chain and saving stronger heals like dull pain for when you really need it. The only time I ever used a siphon power for the heal itself was when I played a tank and my dmg res was high enough that I could use it as a primary heal without losing that hp again immediately after attacking. When you play a scrapper that's usually what happens, the heal isn't high enough and your res isn't high enough for you to use it as a legitimate heal, especially when running 4x8. So while this could be an interesting change, especially for theme, it ultimately won't be very effective because the heals aren't very good anyway, and most aren't going to waste that many slots for a weak heal, unless of course the set bonuses are well worth it.