I don't think Marcus wanted to reshape Earth or the Federation. He was just worried that we would lose the war with the Klingons and wanted to reshape StarFleet to defeat the Klingons. Thus killing them from afar would have accomplished that goal.
Came across this interesting article:
I guess this explains why some things don't make sense if the writer's craft the story and then decide who the characters are and if their backstories work in the current story. I thought things felt shoehorned in, and this just confirms it.