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That...doesn't completly answers my question. I wrote in my post that I'm aware about reputation with factions mechanics. Sorry if all of text made you skip that.
Fact that reputation with people can affect somthing beside them joining your caravan is new to me. Thx. I'll be more wary of that one.
To specify about general? reputation:
Friendly - no use found
Trustworthy - unlocks some scenes and dialogue, like convincing Apis to tell you about Lois when working for Drekar.
Rational - unlocks some scenes and dialogue, like recruiting Spencer. Is it even used after getting to Alkubra?
Smart - seems to mostly work in the same scenes as Rational and is seems somewhat more important.
Virtuous - unlocks some dialogue, like when convincing Spencer to go back to Kivil.
Tough - used in some scenes, like convincing Lois to attac Drekar just with us. Not as important as it can be grinded by defeating strong enemies
Slaver - extremaly important for storyline, but very easily (if tediously) controled by releasing slaves.
Lawbreaker - makes police attack you. Controled by bringing prisoners.
IMPORTANT PART STARTS HERE!!!!
...that means that we can disregard Tough, Slaver and Lawbreaker in dialogue options, as they are grindable, leaving us 4 to worry about, of which at least 1 seems completely useless (Friendly) and one other has seems to only be used in early game (Rational).
Also some hard numbers on lowest amount of general and personal rep needed to don't miss anything would be very nice.