For adapting science fiction to a roleplaying game, you'd need to combine the technological issues with plot device levers. So, if you want a roleplaying game featuring the introduction of power armor (EXO Squad), you need the armored suits to occupy a significant portion of the theme. Beyond that, it would be the question of the suit's effect on man, in the way you write the theme and interaction. Claustrophobic themes, for example, or fear of homelessness for the theme of space exploration, for something involving the 'jumpsuit' power armor suit you see on occasion in fiction. Warhammer 40K performs both of these themes well, in its depiction of human culture in the Space Marines, since the selling point of the theme is the power armor itself.
Take a cool idea, not necessarily something futuristic (Dr. Strangelove, directed by Kubrick, covered nuclear weaponry), then for each idea, analyze that way you'd feel using it, both consciously and subconsciously. The rest is art.