With no dihedral, the wings look like they are drooping. With 1 inch under each wingtip, that illusion goes away, and the wing appears flat. That gives the bennefits of flattening the wing, and the plane still looks good.

Another interresting modification... change the shape of the tailplanes, and the Kadet Sr looks like a Piper Tri-Pacer. Just add the struts. Its easy to change the shape since the tailplanes are built up from sticks. Just keep the same total area on the surfaces. This would have the fin moved back a bit, and the elevator split, requiring a Y elevator pushrod, or dual elevator servos.