Interesting.
If it were my project, I'd have smaller top shelves to create more headroom on the bottom floor, maybe just because I raise big rabbits. I'd also get rid of the ramps, and use 14 gauge floor wire instead of that hardware cloth.
It could be nice for one bunny who mostly potties where you want it to, and mostly chews on what you want it to chew on. My experience is that as soon as you add a second bunny, good potty habits often fly out the window.
I wouldn't even consider anything with that much wood for breeding in.
Now I'm thinking I need to build one for Mucky, nice litterbox using house rabbit that she is!
I wouldn't even need the poo drawers for her. I'd just add a couple removable litterboxes in her favorite places.