That would completely change how I vote. I vote by comparing a post's score to the amount I would give it if I could pick a value. If they're significantly different, I vote accordingly.

If you're really curious checkout Perlmonks.org. It's been around for a decade and has consistently maintained a community that more closely resembles this site than any other I've seen. Blind voting has been in use there for a very long time and has worked quite well. You're also alloted a limited number of points per day based on your karma (XP) level.

>> (or perhaps only hidden until after you vote but I don't see why they need to be there period)

That's an interesting point--why does every site need to quantify for the user the particular score of a comment? Why not indicate popularity by simply ordering the comments?

Is it a trust issue?

Karma -> karma whoring -> pageviews -> profit?

Slashdot no longer displays numeric karma and you can disable display of comment scores.

You could also give other clues besides ordering - without revealing the numbers 'in your face'.

What sort of other clues?

For example color-shading. While it may still be possible to re-extract numbers from the colors --- psychological colors may have another effect than numbers.

Or perhaps something like Nethack does: http://www.steelypips.org/nethack/pray.html#p0

That's sort of like what Slashdot does for karma. "Karma: Excellent"