Indeed - has anything changed?

If not, then those discussions are still relevant, and there would be value in skimming them rather than simply repeating all the points again.

If so, then it would be of value to see what has changed, possibly by reading the previous discussions. Perhaps the mood of the audience has changed, perhaps the general opinions of the HN community have shifted.

Either way, being aware of the past is of value.

    Those who cannot remember the past
    are condemned to repeat it.

        -- George Santayana

EDIT: People often misunderstand these back-links. They are not intended to scold people for submitting things that have been submitted before. On the contrary, I believe some things should re-surface from time to time, bringing them back either for the informing of the newer community members, or for re-evaluation in case things have moved on and should be re-considered. My main concern and motivation is that previous contributions should not be wasted.