Went back to using proper unit frames for the party, and pushed them a little bit center-frame. It's a lot shorter than the player frame is, and the health bar is thicker. With a much narrower power bar, just to have it present without putting too much focus on it!
Also got the ToT/Pet frames in proper, woo! And decided to try something new with the bottom bar. Made it just a single bar wide, and let the bottom right bar float on top of of it. Suppose it looks a bit tidier, so to speak, to not have it span too wide?
Beyond that, experimenting with a castbar that overlays the power bar. On one hand it's kinda nice, since it looks tidy and saves space. On the other hand though, it's not near as easily noticeable as a castbar that actually pops up. Definitely want to revise that. And then maybe do unit indicators and auras next.
Also trying to think of a name for this thing. Been thinking stuff like... Ashblade, Blackblade, Blacksteel, just pluck the name right out of the dark-grey main colours and the metallic grey accents. Blacksteel has a funky ring to it, and it's also an item set in Draenor!