I like your plan. Looks fine to me. I've been playing with plans for my first coop. Not unlike what you have. I'm looking at a 8x12 building divided into a 8 x 8 section for chickens (I'm thinking a dozen or so)with a 8x4 room for storage and with the nesting boxes inset into it with a lid so I can collect eggs from the inside. I am thinking of a total of three doors, the door to the storage area, a dutch door setup between this room and the coop area, and one going out of the coop into the run. And of course a small chicken door. Probably one window in the storage and one in the coop but closable vents near the top too.I'm thinking if I set it up a foot and a half above the ground I can enclose that area and add some run space.