It is not a case of looking good, it is a case of flying an aircraft with unknown propertys due to the changed wing shape.
I would agree that a small amount of hore frost on the fuselarge is not likely to result in any aerodynamic problems with the flying of the aircraft however will it result in problems with the static ports and give errors in the ASI readings ?
Older low tech wings are likely to be less effected by ice however the newer composite aircraft are using wing sections that are far more advanced and the shape is far more critical so much so that gliders are fitted with devies that clean flys from the leading edges in flight to maintain performance.
The whole ice subject is so fraught with unknowns that the only policy in my view is no ice unless the flight manual offers some advice on the subject.