I've always loved the Strikers art. It's like a cross between Jet Set Radio in places and the hand drawn Mario art you used to get pre Mario 64, quite an awesome mix. I still kinda wish if Smash Bros. would go in that direction for both in game and promotional art. :lol
I also now kinda understand what you mean in regards to Nintendo playing with it's iconic character's art styles Willy. It's been a while since we've seen them do something on a visual level to the characters and it'd probably bring a new look at things with the right execution.
Orioto, while I kinda see and agree with what you're saying as well, I dunno if I'd go so far as to say that the current Mario is bland. I think it's more that depending on how the visual design is played up, his charm is either amplified or kept at a median which thanks to continued exposure since his look/CG debuted in the N64 days seems kinda "stale".
When I look at Galaxy (sorry for continuing to harp on this, it's just my go to for imo the best interpretation of the character and universe thus far) I still see the whimsy hero I did stemming back from as early as Super Mario Bros. 3. There are times when the execution of the character's design and the universe itself emphasize the design and make it take on that timeless nature and throughout both Galaxy 1 and 2, this held true for me.
At the same time though, when you see this same design used in "sterile" or maybe I should say more conservative games from Nintendo (in terms of visual design) like the New Super Mario Bros. series, the Sports spinoffs, and the Kart/Party games, it does seem sort bland and lacking something, even though it's clean and colorful enough that you don't think much about it.