There is no reason for it to be treated as multi-target when it's a single target spell. She's a close range mage and needs to be in your face to deal damage with twin fang. There is no reason to have it magically not do full spell vamp. It would not be overpowered.

Please remove this magical multi target nerf and allow it to be treated as a single target spell for spell vamp.

...because you can hit it three times a second if you're quick and use smartcast, I'd assume.

Because supposedly she'd be too strong with Rylais + Spellvamp. Although I don't see how that warrants inconsistency.

Because it's VERY spammable, similar to Karthus Q, even though Cass' E is the only single-target spell treated as multi target.

Guinsoo has stated that the reason for this is so that players can't abuse a 35% slow that can be reapplied indefinitely

Too exploitable with spellvamp/rylais.

It's due to the frequency it can be cast.

looking at the other posts in this thread.. it must be due to the fact that rylias adds slows and stuff.. just my guess though