galaxy 1 and 2 done that for wii, i liked sunshine but preferred Mario 64 and galaxies games so much more, due to wii limitations, the worlds in galaxy had to be kept small, but imagine
bigger Mario 64 style worlds, and a huge open world based in the mushroom kingdom, like super Mario
bros 3, with the giant world, water world, ice, etc i want a 3d super Mario
bros 3, but with a mix of galaxy 1 and 2 and Mario 64 game play,
while i liked Mario sunshine, i quickly got bored of the tropical island setting, and music, and the water based game play just didn't do it for me, and for most Mario fans, the sales speaks for itself, the fact is most Mario fans did not like sunshine.
And playing with others is definitively the way go, not only because
bros will keep you company and make the experience somewhat entertaining, but the game can get quite difficult when playing alone, as enemies can easily swarm you and dispatch you, and
while you can dodge,
big enemies always seem to catch you once the dodge animation is done.