If had I it my way I would redo the complete system. Remove rating and only have a 'like' option.
I'm not encouraging the other extreme of no negativity ever allowed. But the 'like' system would still be a rating system in itself.
The more likes the better the rating, if you see a comic with a thousand likes and only twenty chapters, you know it's a high quality one. And vice versa. A webtoon with a hundred chapters with only ten likes isn't a good ratio.
As for reviewer, like Amazon, you can have verified reviewers who review things based on a more neutral stance.
E.g. A reader that review things based on genuine story writing/art composition etc. and have read at least 3 - 5 chapters to make a review.
These would be chosen through the same way Amazon chooses their reviewers. ( A standard needs to be met).
Would avoid the whole bomb rating.... some one posted my webtoon link on reddit and I got bombed despite not uploading anything)