Enders admits that a380 hairrifts are some obvious failure and airbus obviously failed

like I wrote before, I think the heavy turbines at the end of the wings cause the vibrations because they weigh too much. I didnt get anyway why they didnt put it like a tristar. If they cannot build it like the Concorde, engines close to the torus, they could put one bigger engine simply at the tail of the plane.
I mean the point is really that the result is that you got in the middle some gold bar and to the left and right a bit of plastics. They wanted two levels. But: the torus is heavier than one of a 747.

The wings are shaken easier because they carry more load.

Its not space. Wings do carry a plane. The load is on the wings id est air. If you use turbines and not rockets where one might be enough, you need to keep such things in mind.
Well, they obviously liked the position of the turbines for increased manoeuverability. But then, you could still have built some tristar and additionally two small steering engines at the outer positions.
n-tv

wiki: giant plane comparison

If you look at the 747 see also that the wings are more crooked, id est when the wings connect to the torus the area they occupy is more huge.

see also a14