i could really see soem camera issue here. i think you need to start to buy a new camera. the resolution especially for the night scene is quite noisy. i dont know if its because of post processing or not. but i could say that the mid tones color are gone because of wanting to push the light areas more.
as for the day lights, signs of burn out are already there.
btw those sunsets are good. but if you will have a better camera. you will find that you will have much better quality pictures.