I really like Paper Mario, but the quality dropped a bit with the last one. I kinda wish they kept the same style as the first two. Of course, one reason I liked the Paper Mario series is because of how they take normally bad characters, like Koopas, Goombas, and Boos(especially Boos) and give them a voice and personality.
I don't expect a new Paper Mario any time soon, but I hope that they return to the proper style of the first two whenever they get around to it.
I would LOVE another Luigi's Mansion(a very underrated game, it was brilliant my opinion). Plus, I'm a big Boo fanatic! But it would be even better if you had some ghosts on your side, you know, for some character plot.