
Right. The art is one thing, but the main issue for me would always be pacing.
Some creations would have a few panels where their characters aren't doing anything or would focus more on the sceneries or object, which allows us to properly enjoy the pacing without every moments needing to have the characters do anything.
Some would always even draw simple aesthetic background, sometimes flowers or sometimes just pretty color going along a few panels as if guiding the readers.
And my favourite of all, I love when the arts are depictions of the character's mentality, which I've only seen in a few manhwas. It would be light and colorful when the character is in good mood, drawn in chibi style to depict child-like imagination or drawn in chaotic dark or vibrant color to portray the character's stress and anxiety.
And here I go, rambling again. sorry!

No no, that's exactly the point. All those empty pages and unrelated backgrounds gives life to the world building. To the backstory. To the character.
When the story is all just action, action, action, it's just a shock to the system, while making the story even blander than hospital food. There's no...art, so to say.

The person overseeing he project also left after season 2, and they've changed the writer every season so I bet it's a combination of those two things happening at the same time. Hopefully either the new overseer gets used to it and slows the pace or they get a new writer again that's able to adjust and allow for more downtime between action scenes.
Honestly, it's not that weird for novel adaptations to change their art style. Not all artists are able to hold onto a single project that long, unless they're the creator. It gets tiring after a while.
No.
The point is, what kinda irks me is the pace. The flow of the story is so obviously rushed it saddens me. I've read manhwa where the artist changed and the storyboard changed but the flow stayed the same. If it's rushed from the beginning I'm not questioning it, but with the way it is...
And no, I'm not blaming the new artists. You do know that a storyboard needs to be approved for the artist to finish the drawings? Unless I'm wrong, there are steps to produce a comic, and a single artist can't do everything own their own.