Yeah, his front feet are to steep. Back feet are close to being to steep but ok by the looks of it.
A lot of walkers are on the thin side, yours is slab sided and that's how most of them look. He is under weight but not by as much as you probably think so you'll have to quit comparing him to those QH's in the barn. What you need to look for is how much fat he has sitting on top of his ribs. If he has a nice pad between that and his backbone he's fine. Don't expect a big butt, broad back or a lot of padding over the sides of those ribs.
Get that roll of fat going over his ribs and muscle him up and you'll see a different horse. Just don't put him side to side with a QH!