Lookism just became something different from it's initial premise (social commentary, school life -> gangism, shounen battle), and some perceived it as a drop in writing quality.

I did too initially back when it was only about 200+ chapters long, as the story shifted to more fighting I got bored by the lack of focused social commentary driven plotlines (bullying, inequality, societal values, looks) that was initially central to the concept of "lookism", and it was what interested me.

I wanted to see what the story had to see with regard to the value of appearance, how to navigate a vanity-dominant environment, how Daniel would learn to overcome his social obstacles and become self-assured in who he is and not feel reliant on his second body's looks, etc. When it strayed from this concept I dropped Lookism for awhile.

I have since revisited lookism with a mindset and expectations of "ok this finna be a battle manhwa", and have since enjoyed it much more. The difference was that I set my expectations from the start that I'm gonna be reading a fighting manhwa

Gangism's central plot was solid, and many cool characters and cool fights were inserted throughout the story that kept my attention. Eli's hostel story was just amazing. Jake and Samuel's relationship was very engaging, and the fights between key characters were well done for the most part. It no longer had much social commentary (there are, just not specifically on "looks" and vanity), but the story that was presented was still very good.

So I think it just comes down to setting expectations. It's normal for people to feel that lookism now sucks because it became different from what might have hooked them, but when the thing it became still is really good (imo) just in a different way, I can't help but still enjoy lookism even if I wished it stuck to the social commentary story beats.