HC Crit EK witch[Need help/suggestions]

So i decided to make my own EK witch, since i love EK as a skill. Now since EK feels like an assassin-ish themed skill, going crit makes sense to me, the skill just would not feel complete without that.
The idea would be to use a power charge on crit gem so i do not have to pick up dual curse and can run projectile weakness, as such i decided that the best thing would be to pick up all of the power charge nodes, even on the STR part of the tree, as i would be going in that direction anyway and the aura nodes along the way could be helpfull as well, for hatred.
After establishing the offensive nodes that i would want to go for, i realised that getting health on the witch/shadow part of the tree is a major pain and breaking even 150% seemed hard, so i opted for ES and this is where most of my issues come from as i have never done an ES build.
So here is the final skill tree idea:

NB! I am planning on doing self found HC!
My questions/issues:
-Is this idea even HC viable?

-How good is EK in general

-Would this build be HC viable and what overall feedback could you give me on the tree

-How would i go about leveling this, because from what i gather going ES from the very start is not smart, however with the 18 passive refunds i can get from quests i can not really afford more than maybe 100% life, and i do not want to rely on finding regrets.

-At what point could i start going ES?

-Lastly, should i pick up pain atunement and go LL or should i pick up CI? i would immagine CI unless i find one of the items that make chaos not bypass ES...

That would be all, would greatly appreciate any feedback/suggestions/answers! If i think of anything else ill edit that in...

This tree will not work.

If you want an ES build you have to take CI otherwise chaos damage will kill you. I assume you don't have a shavronne's wrappings in your stash.
If you decide for a CI build you usually level as a life build because it is easier to get good life rolls on gear than high ES values especially at lower levels. You also have a bigger choice of gear for a life build (everything can have a life mod but ES can only show up on ES gear which halves the gear pool you can choose from). Speccing into CI is usually postponed until ~act 2 merciless. By then you should have gear ready that gives you more than 5k ES (in HC i think 6k would be the absolut minimum).
So if you think about playing selffound HC (on your first HC char) you better make a life build.

EK is best used with a life build because you need almost no blue sockets for EK (maybe 2 for spell echo and faster casting). All other gems (EK, faster projectiles, life leech, added fire, empower) need green and red sockets. It is hard to roll the right socket colours if you wear pure ES gear.

You also made some odd choices in your tree:
Frenetic instead of Doom Cast.
Block nodes are a bad idea when taking acrobatics due to the block penalty.

You won't be able to sustain your mana needs with only 20% mana regeneration from the tree and no mana nodes.

Maybe you should look at some of the EK guides that are linked in the shadow builds list.

Thanks for the feedback, CI was not taken in the tree because i wasn't sure about CI/LL, i have no clue why i did not pick up doom cast there.
And acro was a bad move as well, i only focused on that it reduces armor, forgetting about the ES and block penalty.
I made a few revisions based off your critique, and came up with a way i could level this while only needing to respec 15 points at about level 55, but i guess a shadow would be more appropriate here, considering the green sockets i need for this, however, if you would humor me, is the tree more viable now as a physical crit spellcaster tree?
Full planned tree:

Leveling tree:

Not worth picking up:
Thrill Killer
6% increased spell damage at the scion start
Depth Perception
Shield nodes in the witch area
Piercing shots

Should be taken:
Sniper - Coordination - Soul Siphon
Essence Surge is a must have for CI in 2.0 imo.
Ghost Reaver (if sticking to CI)
Vaal Pact in the new 2.0 tree

Overall it will be very tough staying alive with this build in 2.0. No damage mitigation aside an ES pool might work in SC but i'm sceptical it will in HC with the higher monster damage.

You should really look at some of the shadow guides for some info on tree layout and gem setup. They can easily be changed to start as witch.

BTW As 2.0 is only a few days away you might want to use this: http://cb.poedb.tw/us/passive-skill-tree/