If we are still hoping and praying for a solution at left tackle from a mid round pick or a backup we signed in free agency then we haven't actually improved until shown otherwise. You can litter poo everywhere here in the meantime but reality is reality.
I wouldn't exactly say we "lost" Chris Reed.
And yes, Russell Okung made the line better when he was in. Unfortunately, that doesn't matter when you can't count on him to be there from one week to the next.
So yeah, if we're going off last year, ranking us low is fair. Realistically though, this year is an unknown and people making predictions are just throwing crap at the wall.