I'm not concerned about the appearance or the wing coming loose from the plane. The concern lies with the 2 wing halves not being glues to each other as COMPLETELY as they would have been if he had applied glue to the root ribs and they were in contact with each other. POSSIBLY less strength here could allow the wings to fold in flight but as I said, not much to be done at this point.

Covering the gap with covering or at least tape will keep fuel/oil from getting into the seam and causing damage though.