The pre Red Faction is possible but dont have license to Red Faction anymore, probably Purple Faction. Going to Zin's home world? not sure is that a good idea and it sounds bit like a major DLC or standalone DLC to me.
To be honest, I really have no idea how they are going to top SRIV. With super powers now, the only thing they could do maybe is more super power and a better city but maybe set in real world instead of simulation since the kid from Trouble with Clones DLC able to make some sort of super power juice. They could do something like Deus Ex with all the cybernetics stuff as well, I would love to see that.
To be honest, I really have no idea how they are going to top SRIV. With super powers now, the only thing they could do maybe is more super power and a better city but maybe set in real world instead of simulation since the kid from Trouble with Clones DLC able to make some sort of super power juice. They could do something like Deus Ex with all the cybernetics stuff as well, I would love to see that.