Is there any way that I can improve my iPhone 4, physically?

I am using a 6+, but I just don't like it. It's too big and thin, I just don't feel like holding it. Out of the iPhone models, I like iPhone 4 the most. The only reason that I don't use iPhone 4 is the camera and safari speed. It takes forever to take a picture, and if you don't have a steady hand, the pic is gonna be super blurry. For the browsing speed, iPhone 4 is nowhere near iPhone 6. So if there's an iPhone 4 that has the same camera quality and safari speed, I would just throw the 6+ away. Is there a way that I can somehow "merge" these 2, the look of iPhone 4, and the features of iPhone 6? Is there a way to build like a better camera in iPhone 4? Like, if I take everything apart, replace the camera 4 with the camera 6, or however you do it, is it possible? In other words, is there a way to squeeze the inside of an iPhone 6 in the outside of an iPhone 4?