This is what happens when you forget to put your glasses on.

The first image of the eye is the only one of the 4 main comparisons, where the new could possibly be seen as being better, but even then the eye looks like a polished chunk of quartz, not a human eye. The human eye does not reflect like that. Detail is a split, with the old image showing hair follicles and a bit of oilyness on the bridge of the nose that are no longer visible, while the new image shows some dimples that were not visible in the old image. It appears to mostly be due to the major changes in lighting in this scene though.

The second image, the lighting is better in the new image, but the textures on the outfits are completely plastic looking. It looks like a cutscene from a PS1 game, with no textural detail at all.

The third image is the most obvious downgrade, with Wedge's pauldron and gun looking like plastic toys. Again near zero texture. The 2015 image the pauldron actually looks like worn metal, and you can clearly see the rivets. The new image, the rivets are barely visible, and there is a very noticeable blur over it. The leather straps on his armor looked like actual full grain leather in the 2015 image, while they are very smoothed over and lacking detail in the new image. Clouds sweater is also washed out and lacking detail now. Even the lighting in the old image looks better here, due to how washed out everything is. The only upgrade here is Clouds face and hair.

The fourth image, it is harder to tell as the blur is so heavy on the 2019 image. But you can still see a substantial loss of texture detail on the clothing and armor.

The image of Aerith at the end is the only real upgrade. They actually removed DoF on it, which is nice. But this is only May-Dec of this year, not 2015.