I second the ambivalence about inclusion in Steam, even though I'm a big user of it.
There's not a whole lot of reason for us to go out of the way and pick it up there, unless you wanted your friends to see that you've logged 10 zillion hours into DF or something.
It would attract a lot of new eyes, though, that's for sure. But I don't think most people who'd see it in passing and download it would really enjoy the experience...I can imagine swarms of comments along the lines of 'bugged as heck, game suks' and 'theres like no directions and i don't knwo what to do, this is dumb', and so forth.
DF's the kind of game where word-of-mouth is more effective than other types of exposure; those who have an idea of what they're getting into before they dive in will be way more likely to actually enjoy the experience. Perhaps in the future when the game's more steamlined it'd be more suitable for Greenlight, but I feel it'd be not particularly viable right now.
As for 'trading reputation in via Kickstarter', I wonder how well that'd work? As far as I can tell, people like Toady/Threetoe because they seem like cool guys; they don't charge for the game, they refused a six-figure deal for the name, always in constant contact with the fanbase...all that and more has generated a lot of goodwill for them and the game in general. Kickstarters get a lot of notice and it might do more harm than good.
But then again, the sponsorship drive was similar, and that went fine...so what do I know?
I'm surprised merchandising wasn't mentioned at all, actually. I'd buy the crap out of a DF shirt.