[Theory Crafting] Vampire build (life leech/gain)

So I was looking for some life leech / life gain on hit builds and I didn't really find what I was looking for. The idea behind this build is to make it rather theme based than efficient.

I would like to have life regen coming from hits as well as from leeching, meaning I need to hit fast and deal great amount of damage. If usefull I would also get some life leech and life gain on hit support gems - depending on how good they work.

The notable passive skills to make this build vampire theme based are as follows:
Hired Killer, Blood Siphon, Blood Drinker, Lust for Carnage, Hematophagy

As weapons I think dual wielding claws would be a great choice, making these skills a preferred addition:
Claws of the Pride, Soul Raker (also gives life/mana leech), Claws of the Magpie

Scion seems to be a good class to get these skills without spending too many skill points. Since Lust of Carnage goes into the other direction I was looking for other passive skills that could be picked up on the way, though I'm not quite sure which ones would help the build. Maybe some of you want to recommend anything?


This is what the tree looks like so far - just the main skills unlocked:


Instead of Path of the Warrior, the Sentinel (via resistance buffs) is an alternative route, not spending as much points to get to that side of the skill tree.

Using two claws I decided to pick up Molten Strike, Vigilant Strike, Riposte, and Puncture. So far it worked pretty well. I almost never have to use life regen flasks, but mana is a huge problem. Since it should be a vampire theme based build, mana leech could be used as well. These passives sound promising:
Thrill Killer, Soul Siphon, Mind Drinker, Battle Rouse, Revelry

This is what the tree looks like with those:


The most important questions is, if mana leech and mana gain on hit are really worth it or if I would be better of using points for other skills?


What are your thoughts on this? Really would appreciate to get some constructive feedback on how to skill the passives.