New Malady: a sustain item for atkspd/ap champs

Okay, so for those of you have have been playing league for a long time now, you should know that malady used to provide lifesteal and atkspd. Then riot removed the lifesteal, and improved the on hit effect it had, then just flat out removed the item by moving it's key aspects to both wit's end and nashor's tooth.

So here I am with a suggestion for bringing back malady. But first, let's set up a basis of why.

Riot now, the kings of sustain are adc's. There is no denying, the build lifesteal, ad, atk, and crit, and most items have more than one of those stats attached, so healing up on creep waves after engages is easy for them. But champs who scale best with atkspd and ap (like kayle and teemo) or champs that can't afford many offensive items (unless fed) (like shyvana) really only have 1 item to buy for their sustain issues, and that is bork, and let's face it, bork is not a great sustain item if that is the only ad item you are building. So here is my attempt at a solution:

Malady: Builds out of 1 recurve bow ( ) and 1 hex tech revolver ( ) [why these items? they look nothing like swords. I get that, but right now, I'm going for the stats they provide, not what they look like. Also, recurve bow now builds out of dagger because REASONS]

Stats: 50% atk speed (can be lowered to 40% if necessary) 50 AP (can be lowered to 40 ap if necessary) Unique Passive: Baneful Strike: Each aa deals X (+.Y ap) mag dmg Unique Passive: Harvest (yeah, I suck at making names. Suggestions welcome): Each aa heals champ for X (+.Y ap)

The reason I chose a flat heal with a small ap ratio rather than a lifesteal clone is to help with possible abuse cases, and to allow the item to be more easily balanced. Also, this item should be more effective with higher atkspd rather than higher dmg anyway.

Any suggestions and/or constructive criticism is more than welcome. Also, what are your guys' thoughts on sustain for non-adc's anyway?

EDIT: So I've been noticing a lot of comments about spell vamp. First, on-hit effects (whether from items or kit) presently do not apply spell vamp. Now, a lot of you have been suggesting that we should just let spell vamp apply to on-hit effects.

The problem I see with that is this: spell vamp is an inherently broken system. Riot has admitted this already, and thus I wished to steer clear of using it as a solution for atk spd builds.

Also, on-hit effects are not limited to mag dmg in nature, hydra has an onhit effect, so you'd run into some wonky situations with hydra and gunblade having a weird synergy if this were allowed to happen. But then you might say, "well, just limit spell vamp to mag dmg only" the problem with that is spell vamp currently works for all spells, even phys dmg spells. If we were to limit to just mag dmg, that would be an indirect nerf to akali, who's pbaoe spell deals phys dmg.

See the problem with spell vamp? It's messy, and a can of worms I don't want to open.

Also, you guys seem to be afraid that this item with give some kind of ungodly sustain. Long story short, it will not be nearly as good as the kind of sustain an adc can get with a full build. End story. So don't worry about that.