The reference to legacy glass isn't to Sony legacy glass, but to the likes of Mamiya, Hasselblad, Pentax, Pentacon and others. A tremendous variety of adapters

The reference to legacy glass isn't to Sony legacy glass, but to the likes of Mamiya, Hasselblad, Pentax, Pentacon and others. A tremendous variety of adapters are available to adapt almost every removable mount lens format to the Sony E mount for their APS-c and full frame sensors. A curved image plane is more associated with box cameras like the Ansco Pioneer or with pinhole cameras, to either reduce curvature of field or vignetting. Most likely the curved sensor will reduce the complexity of the lens since it removes the necessity of creating a flat field. It's certainly possible that Sony won't make their own camera, but will instead sell sensors to other manufacturers just as they do with APS-c sensors.