Well to start with 'rich in' has no meaning especially when you admit that you only put 17.5% of the ingredient. Cereals is a generic term which involves not telling you the whole picture and ability to hide or flex ingredients. Oats, Barley, Rice, sweet potato total 50% is quite a high carb level for dog food. Oats and Barley are cheaper ingredients than Rice and sweet potato but rice/SP is lesser amount. Antioxidants is common to use and good for dogs, Beet pulp is a good source of digestible fibre.
My opinion a very average food If you had the Vit A level and it was about 25IU / KG it would be better but I doubt it.