The mk6 is only being brought in cus the VW are not making enough profit with it. Bring out something thats cheaper to produce in mass numbers, is a no brainer in any bussiness.
Im sure the Mk5 will be hard to better, tweek it maybe but this mk6 is not from a clean sheet of paper. Why scrap a popular model altogether if it works, Visual tweeks is all thats gonna change, underneath except the engine will be very simular (and Cheaper Suspention)