Focusing on the bigger picture actually a good thing, but I think it suits One Piece more than Hunter x Hunter because HxH is mostly about the side-quests instead of the main one. (One Piece has equal focus on both.)

I find even Hunter x Hunter's "bad" pages charming in a way (maybe because they make me feel like I can draw too 😂).

Me too~

The 1999 version looks better at its best, but the 2011 is more consistent with its quality.

I believe that's the reason. I always prefer 1999 version when it's at its best, but 2011 had better pacing and consistent quality & I love the contrast between the childish art style and the dark themes.