Hi! At last I got to visit your entry
Got to warn you that I’m a noob, and as such processing my words through brain quality filter is a must.
My first word is … Wow~! The sketches and the lines hooked me in. The concept of the polycount dude got screwed is just great. Loved the idea of branches growing into caesarian crown, good utilization of cliche. Because it doesn’t have leaves it looks like Jesus’ thorns, but I also like it that way. Face is very expressive and I’d want to see the feel sustained in 3D. I also got reminded by your photos on how vegetation looks different on the other side of the globe 
The clothing from waist down + 2 pairs of sword in the very first picture flash in my eyes. Got to admit that I’m a FAN of that kind of shape which somehow I found more on sf (this, this, this) although there’s this too. To me it denotes speed since everything is pointing backward and spreading. The big sword also looks speedy. Looks great especially on the first pose, though it’s not working on last pic no. V for example.
Last pic no. IV also strikes me. I just love the armor shape on the torso, hip, and pelvis. The flow is very nice. Doesn’t seem to have any hint of tree though (I know it’s because of the storyflow).
Anyway, about the -wow- thing you asked about: I do think that the polycount dude screwed up pic is really wow. Maybe you can implement this on the winning pose, turning it into a bit of diorama. Large amount of branching from the body covers much of the body’s design though. If for example, he’s standing and only his arm (or something) spread upwards into branches stabbing the polycount dude, you got the: ‘wow’, design, details on both thing, diorama, all of them in one shot. Looks better presentation wise, although more cliche stuff is going on. Not a good model for game production and it becomes more of a game art sculpture but well, the wow is there.
About the wow and balance thing, usually what happen in my mind is: plug 1 or 2 main design highlight(s) that has dominant silhouette + detail, then put secondary highlight(s) which is still a bit strong but less attracting away from the main one to balance. The rest, slap tertiary detail/highlight here and there to balance more and make the eyes travel around. Sounds kind of like composition on illustration but basically it is. May not work for everything and since this is devised by noob like me don’t just gulp it to the brain
Somebody please crits me too if this is apparently wrong.
Sorry for the long post, especially in other people’s thread, but hope this can help. Great job so far! 