Mario looks really good in that picture. Like, "Hey guys, look! I'm back, and I took care of the angry impostor who was in Brawl! Didja miss me?"
As for Fawful, yes, we all like him. I think he's a bit overrated, but he's cool. Can't wait to see what he's up to now.
I'll be sad if E. Gadd doesn't return. When he first showed up in Luigi's Mansion, I thought, "Wow, Nintendo CAN come up with good 'mainstream' Mario characters!" Then he just had allusion after allusion and only really appeared in Superstar Saga and Partners in Time. I like what they did with him though, expanded upon his scientific expertise while still leaving a heavy emphasis on his passion for ghost research.