Ferrer and Davy can't do much with just talent alone. Had they played in the 60s when height wasn't an issue, who knows how much they would have accomplished.
Including Davydenko doesn't really make sense because his groundstrokes are punishing and his serve had some pop too, it was just inconsistent. It was never lack of power that limited him, it was his mental breakdowns. And he's 5'10, same as Hewitt, Agassi (Agassi was maybe 5'11), and Chang who was shorter yet won a major and competed in 4 slam finals.