Greg responds...

Well, it was less about spin-offs and more about occasional guest stars. Then if someone (in authority) had said, "HEY, DO THAT!" we would have.

I think I've mentioned we wanted to use Johnny Storm, so that could have led to a theoretical Fantastic Four spin-off.

We wanted to use Beast, Cyclops and Professor X, which could have lead to a theoretical X-Men spin-off.

We wanted to use both Hulk and Captain America, which could have lead to theoretical spin-offs for either and/or for the Avengers.

Oh, and I did have one other spin-off idea that really was a spin-off coming out of Season Three or Four, that would have largely featured characters that had already appeared in the series by that point, including (but not limited to) Flint, Hobie and Felicia.