I don't mind the looks of some of the wings in GT5. More variety between the wings themselves, and pylon placement and angle would be greatly appreciated though. And for me it depends. I rarely put wings on cars just for show. the only time I do is if its a drift car. Otherwise the wings will always be there to serve a purpose. For example making my Volvo Estate just a little bit faster through the twisties. As well I tend to forgive aesthetics in the way of function. If it make the car faster, I won't mind it that much.
Though i will say outrageously huge wings on cars that you know just by looking at them, weren't meant to go fast, just look bizarre.