Yeah I still firmly believe Ash should've won in XY&Z. Though I think it's good Z-moves weren't around then either.

Honestly I'm still one of those that don't like the look of the anime in S&M. Ash didn't look the same as everyone knows. Whether it brought out more expressions or not. It just didn't fit the style Pokémon have had and should have in my honest opinion. Even Pikachu looked....weird to me. I didn't like it at all. I looked forward to the movies because the animation in those were BEYOND beautiful as it was in XY&Z. With S&M it's like they took a cheap small production crew that was new and said "have at it." Almost like a fan production (which would explain Ash actually winning for once). That's just how I feel whether others believe it not. It's my opinion. Doesn't mean it's that way for everyone though. As everyone has their own opinions on it.

Like Neo said. It's also a part of the impact they bring to light. Sometimes it's characters or certain aspects. The PMD games are a very good example of that.