The old wing may have used a philosophy with a weaker up wash from the wing going downstream to the floor and undercut. That is a smaller wake.
The new wing has more elements and gaps, so should in theory have a stronger up wash behind the wing and a taller wake. To adapt to this the floor entry was raised it seems.
Whatever they were thinking with the first wing was probably one of those overcompensations Russel was talking about.
It may have been in aid to have lower drag over the wing and also a less peaky floor with a lower opening.
Now they're going more aggressive. Just my opinion.