Could a wing be designed to exploit both normal flying and ground effect?
Ground effect is measured using the non-dimensional height parameter 'h/c', i.e. the height above ground divided by the chord length. By increasing the chord length, the height of the maximum efficiency height is raised, as the location of the h/c does not change.
Increasing the span also adds efficient lift due to aspect ratio effects, however creating too much lift is not always better, because it will move the operating altitude above the most efficient height (h/c max).
Ground effect therefore favours larger chord length to get the required ground clearance, however larger aspect ratio wings are better for atmospheric flight. An aircraft could be designed to operate in both modes, but it will always be a trade-off between efficient ground effect flight and efficient atmospheric flight, there is always going to be a compromise of one or the other or both.