Quote from Arkarian:
"fleshed out" (that expression never made much sense to me)
How about "bare-bones"? Or "skeleton crew"? Or "just skin and bones"?
If I were more awake I'd search through Saber's old sketches to see if there were examples of his starting with a rough framework and adding flesh to it. I'm just completely puzzled why that expression wouldn't make much sense to you.