I agree with this, especially the back angle needing more appeal, I also really like the hair on the opposite side, but it seems completely rigid. I recognize that it adds a great deal of complexity to have motion of any kind, but I think it would significantly improve the over all look & feel.

Lastly, something to consider, I think this helm would look fantastic with Saryn's delux skin, but the flower would be on the same side as the larger one on that skins shoulder, which may create an unbalanced look.

Go big or Go home.

I love how you're sticking to that NY noire style, maybe even 1940s look, but still needs work of course, but you nailed the direction on the head.

Consider seeing what it'd be like on Saryn Prime as well, also good to remember that Warframes are a mix of Machine and Flesh, they're pretty much cyborgs made from a virus. Invest people into flashy and asthetically appealing pieces, and don't be afraid to have parts that flow, or are physics based.

Also one thing that is becoming common, is people either make the frame have "eyes" or not, and I'm sure you've come to that conflict, but either choice dictates how your frame look will be like. Eyes for these can become cheek-ish, or piercing, they can be sublte for people to merely interpret that there are eyes, or you can make them obvious, and strikes a player with how strong it is in its reveal.

Really a frame without 'eyes', will make it seem hollow, as if they have a mask, but added mystery, while adding 'eyes' can add character, make one feel intimidated or even a false sense of security.

Also because you have a portion of the 'face' hidden, you could take advantage of that to do something special.