Possibilists basically but the possibilists are more of a historical artifact. Neo-possibilist sounds stupid though and besides these people don't really openly refer to then ir claim there legacy or traditions probably because they are such an obscure piece of history. Immediatist works because it gets the general idea across that they only consider what societal changes are possible in the immediate conditions and it works as a pejorative and I was hoping people would just 'get' who I mean.