I agree, Wikipedia is not a very reliable source most of the time.

Besides, of all the characters to be given a spinoff, I honestly cannot see Muffy carrying a show by herself; she's too obnoxious of a character to star in her own show and have it be appealing, it'd be like giving Randall from Recess his own show.

I know there's been the fear that "In My Africa" is basically a poorly disguised pilot for a spinoff series focusing on D.W. and Cheik, or however you spell his name... I doubt that'll happen either, but still.

Postcards From Buster was a good attempt, it was just odd to see the second banana carry the torch, and the mix of both live action of animated segments has become an overused gimmick in most PBS shows these days. Arthur is such a true ensemble series, that it's really difficult to try to give any specific character(s) from the show their own spinoff and have it reach a level of success... like with M*A*S*H, after that series ended, they tried to do a spinoff with Colonel Potter, Klinger, and Father Mulcahy, and it failed miserably. Similarly, they tried a BUNCH of different Sanford and Son spinoffs that didn't work, one of which was basically just Sanford without Son... none of them worked.

A successful spinoff would probably be something that kind of takes place within the same universe (Elwood City, or maybe like Crowne City, or whatever), by focusing on a slightly new cast of characters that don't have much significant relevance to the Arthur cast (though they could make crossover appearances)... kind of like Green Acres was to Petticoat Junction, and even what Petticoat Junction was to The Beverly Hillbillies: each of those shows took place in the same universe, but had different casts of characters, and they even crossed over into each of the shows occasionally. If they took an interesting one-shot character from Arthur and gave that character a spinoff, it MIGHT work, but it would all depend on how well it's executed.

If they choose any character from Arthur to do a spinoff of IMO Alex or Maria or both are probably the best candidates for that due to the fact neither have ever been focused upon before. On top of that they are in Mr. Ratburn's class meaning they will be able to interact with Arthur and the other main characters in the class. It's like you said it depends on how it's executed is the difference between the show doing well and the show becoming a bigger flop then the movie Glitter.