For me, this article doesn't seem to provide much insight at all.

All of these qualities would be expected of any person, who is more experienced than some other people, in any field. An experienced foreman is more independent than a day labourer.

What about something like: "A senior developer is more able to reason about interactions between separate, but related systems." Or: "A senior developer is more able to dig into the lower level bytecode of a Java application to debug a performance issue."

While my examples might not be perfect, at least they make an attempt of being much more concrete.