I'll chime in a bit late.
To me, that sounds like a very interesting proposal, and a very problematic one. If we look at video games as dopamine injection systems, you're going to need something to take the easy and overused place of violence.
I can think of two roguelikes that do something like that already, to varying extents. Legerdemain's combat system is cumbersome and punishing, but it's not the focus of the game. Mostly what you're trying to do is solve the mystery of your existence and unravel the riddles around you. This involves a lot of dialog options with manually-entered keywords, brutally twisted and turning labyrinths with hidden doors and secret passages, and an incredibly rich story. So in this case, the author has replaced the thrill of killing with the thrill of page-turning. It's very nice to find a hidden waterfall or discover a part of your character's past.
DF2, in another sense entirely, also does without combat. True, combat is mostly the focus what with the kids these days, but DF would be a complete game without any combat whatsoever. There, it's not so much the thrill of discovery or a richly woven plot that fills the gap, but a physical system that is so engaging that you've got enough to care about without having to care about killing the goblins.
However one would go about it, I think it's safe to say that the player needs something to care about, not just something to do. Basic spelunking/desert/space survival could be quite an enrapturing challenge. Or, were you a race of underground sprites who were trying to explore the mysterious world around them, them having enough charm, history, and/or personality could do the trick in aligning the player with them.
