At the end of the day for the sake of the games success something along option 1 is likely necessary, as it will probably appeal to the broadest array of players while still providing options for those who care. Wanting to implement anything else would most likely warrant actual market research (even on a small scale) to see how people find it in practice. [As a first title I think game success is especially critical in terms of design choices to ensure further development]
Concepts like option two could work if you could find the right balance, though it could still be risky.
Though if this kind of option was implemented something like a number of saves, or a time restriction on how often you can manually save or where you can save would work better then something that effects gameplay mechanics directly.