(Top to bottom: GroVia, FishNoodles, Alva, BumGenius size medium,
BumGenius one-size, Tots Bots Easy Fit, AppleCheeks)
These are all diapers that are supposed to fit a baby in the same weight range. While the difference may not look pronounced in the above picture, here, with the location of the leg elastic marked, it's more obvious:
Somehow, both shapes work well on my 20 pound, 30" tall daughter, though I prefer the GroVias under jeans and pants. However, the shapes of the diapers are so very different that they may not work the same (or at all) on different babies. This is one reason experimentation is key if you aren't happy with your current diapers!
Here are three more diapers, stacked on top of each other with the right edge exactly lined up. (I'm not positive, but I believe it's a Sunbaby on top, a Blueberry in the middle, and a Tiny Tush Elite on the bottom). Again, much different widths that may work very differently for different babies.
Conclusion? If you aren't happy with the fit of your diapers on your baby, try a different brand!