So the programmers intentionally ignored the continuity of old games...
including Super Mario Galaxy 1! I actually looked in and found out. They actually made the good guys not know that Bowser was going to get Super Stars, and he just decided that out of the blue to get Super Stars and grow into more of a giant! JESUS CHRIST! Sure this is a game and it worked many times in the past, like Super Mario 64, but this is too incorrigible for even a game, especially for a Mario game. After almost an entire decade of defective, half-assed plots post-Paper Mario (more damaging to his villainous reputation than his few alliances with his enemies), Bowser becomes a threat again in the first SMG, but is also unwittingly also a threat to himself, because, ignoring the game programming, if Mario doesn't defeat him and destroy Bowser's Sun, it would overload anyway and explode before the Lumas can even sacrifice them, killing everybody, including Bowser. And Bowser didn't even intend to endanger himself with his plot, though he obviously has no problem endangering others. Bowser was so obsessed with such a self-deluded plot that he neglects his safety, and kidnapping Princess Peach has long become a fatal flaw to his plot, even that one.
But what the game programmers did with this one is the most contrived excuse to make Bowser a bigger threat, even for a game! It just makes the good guys look weak! Especially when at the final battle when he seemed to die but came back and ate the Grand Star to become much bigger! WTF?!!? This game's whole scenario could have been avoided, especially after Super Mario Galaxy 1! Mario, the Comet Observatory, and the Mushroom Kingdom are better than this!! And I know they can be smart enough to outsmart Bowser and get to the Power Stars before he does.
There are other ways to make a great regular Super Mario game. Having a lame-ass excuse for Bowser to become a threat again, and have a better chance of survival if Mario doesn't stop him than in SMG1, does not make it a better game. It just makes even Mario look like a weakling, which is something he is NOT!! Also, they good guys such be able to figure out to keep them in a place where Bowser won't be able to find them, BUT NOOOOOO!! Along with the reset button technique when the Lumas sacrifice themselves to save the universe and things get reset to the beginning, they make the continuity of even the previous game invalid. Making the good guys look weak may have worked it the past, but now it's too incorrigible to stay this contrived. And for those of who like the Galaxy games, you all will soon be tired of the programmers implausibly making Bowser, who proved to be an incompetent has-been in practically all the other games, a bigger threat once again, and the good guys look like weaklings again. So that's why there should be an RPG (regular platform Super Mario games wouldn't work for the idea) where the good guys get to the Power Stars before Bowser does and lead him into a trapping using Princess Peach and Fake Power Stars and Fake Lumas and giving him a humiliating Custer-esque defeat and dismissing him empty-handed. Then, as a last resort, he joins with a greater evil to save his own ass, er.. tail. It could end with him realizing how much of a failure he has become in games post-Paper Mario for N64 and helps Mario defeat the greater evil and the Koopa and Mushroom Kingdoms cease their enmity. Or Bowser could be permanently killed off. These are each better than Super Mario Galaxy 2's lame-ass excuse to make him a threat and make the good guys look week. Any regular Mario game could be the same way people want it, but with a new main villain who is be default capable of taking over the galaxy without endangering himself whether Mario defeats him or not, and actually almost benefit from kidnapping Peach like in the past (Super Mario Bros. for NES had Bowser's dark magic only fixable if the Princess was rescued). A fresh new villain for the franchise that can find Power Stars, or whatever, before they can be secured, and who never sides with the good guys even once, and always allies with a greater evil!
Bowser has worn his welcome as a villain, so that's why that doesn't work anymore with him. If he gives up rather than gets permanently killed off, I think he should have his own game series for older video gamers who grew on the Mario games, where he leads his Koopa Kingdom against the new franchise villain including influences of, say, Godzilla movies, action games, and maybe wrestling matches for boss battles.