Storytelling in the Art. I feel like a lot of artists aren't aware or decide to ignore that aspect for convenience.
The core attraction of Comic is a blend between visual and writing so when I read a comic that's able to tell a story without relying heavily on word, I'm amazed.
I'm usually turn off when the art have strong weak points, i'm not only talking about the artstyle but the choice in composition, the variety of angles, the dynamic between background and characters, the world building, the charact design etc.
But I can say the same with writing tho' haha. But because I can easily be fooled and drawn to a story, I'm more lenient when it comes to story. I'm usually okay with wonky or hyper cliché stuffs as long as the artist is effecient to tell his story, visually.