I feel like they really cleaned up on Ash's design in SM. It did look off in the first few episodes but then, as time went by, it started to seem like nothing really changed. The TRio still look a bit off but much better than their first appearances like Ash. But it's an added upgrade for the TRio to show what their persona consist of just by looking at them. Jessie always has this conniving smile plastered on her face (her smile, no matter how it's drawn always looks evil like a witch) complimented by her natural sharp eyes, she breaths a sort of self absorbed yet confident vibe. James and Meowth both seem unsure, "go with the flow" almost childlike in a way when you look at them, especially James who doesn't get much spotlight. It's like in each frame, you can tell their emotion, especially Meowth when he's spooked or feels uncomfortable.