Time to guess the next gimmick.

I believe that for a gimmick to really be GF levels of capable is for it to:
>Not require too much change
>Be battle pertinent
>Be either part of the plot or something the proffesor can give.

I think the next one is going to be type changing. Just think about it. They would be doing less work than megas and gigantamax simply because it wouldn't effect stats.
Also post reaction images.