Have you tried a different brand of cake mix instead? It could just be an inferior brand if they always come out bad. I never use room temp, don't have time, I break all sorts of baking rules. Over mix, use water, different temps, doesn't matter, as long as I don't go too rogue, it comes out fine. But I did notice one certain brand of cake mix is awful and never comes out even when I follow directions to a 'tee'.