Spinoffs don't always have to mean party games, you know. Take the Paper Mario series - it's technically a spinoff, but it's also a very good series. Actually, the Wario and Donkey Kong series could be considered spinoffs too, as the staring characters originated in Mario games.
The difference... Paper Mario is an RPG series that uses characters and the style from an adventure game series. EarthBound's already an RPG, so the backward would be to make a platformer based on it? But EarthBound is all in the writing... I can only imagine a modern platformer with EarthBound's style being like a new StarTropics game (which I
would love to see). Or do you propose more RPGs be made centering around other characters? Mmmmmggghhhhhhh....
I think that the series is better off as just a trilogy. Quality is better than quantity, am I right? It'd suck if Itoi tried milking his brain and ran out of good material just for the sake of putting out more games. I mean, not that he isn't Superman, but his job with the series is done. They're masterpieces and they don't have to be turned into halfhearted money machines, even if (like the Mario series) a masterpiece comes 'round every few games. I feel the same way about Harry Potter. All is said and done.
I'm sorry so many of my recent posts have been so long.