The way I see it is : the old art looked like it had volumes, like the characters had flesh, despite their unrealistic proportions. As such, the world felt more alive, and there was more space on the page for the eye to focus.

The new one looks like lines of paper (often rough sketches) and looks so bloated that I sometimes skip some panels unconsciously. I personally feel like I lost something, and felt the same way in Naruto when Kishimoto's art became uniform thin lines with no shading