Personally I'm not a fan of cross overs. They never turn out well, and I don't think SpongeBob SquarePants would be much of an exception. Think about it. What could the show cross over with?
And as for a new character, I'd probably give them a chance, but there's a chance that I wouldn't like them, knowing what previous Nickelodeon shows have done when it comes to adding new characters.
As for some new ideas of individual episodes, I am still a strong supporter of an episode about SpongeBob and Patrick having a sleep over, where Squidward would possibly get involved. I also want to see them go on a vacation, maybe to the mountains or something.
I just want to get a good idea of what everyone thinks of this idea. What would you guys think if they added a female sponge to the cast?