The analogy that AGI can be to us as we are to chimps. This is the part that needs the focus.

Yes, this is the important part. Chimps lag behind humans in 2 distinct ways - they differ in degree, and in kind. Chimps can do a lot of human-things, but very minimally. Painting comes to mind. They do a little, but not a lot. (Degree.) Language is another well-studied subject. IIRC, they can memorize some symbols and use them, but not in the recursive way that modern linguistics (pace Chomsky) seems to regard as key, not recursive at all. (Kind.)

What can we do with this distinction? How does it apply to my three examples?

After all, a human can still beat the best chess programs with a mere pawn handicap.

O RLY?

This may never get to two pawns. ever.

Ever is a long time. Would you like to make this a concrete prediction I could put on PredictionBook, perhaps something along the lines of 'no FIDE grandmaster will lose a 2-pawns-odds chess match(s) to a computer by 2050'?

BTW, is ELO supposed to have that kind of linear interpretation?

I'm not an expert on ELO by any means (do we know any LW chess experts?), but reading through http://en.wikipedia.org/wiki/Elo_rating_system#Mathematical_details doesn't show me any warning signs - ELO point differences are supposed to reflect probabilistic differences in winning, or a ratio, and so the absolute values shouldn't matter. I think.