Treat different preferences differently

Comments on G. Campbell Sharman “Two-party preferred count is a two-card trick”, 26/08/2010, http://www.theaustralian.com.au/national-affairs/commentary/two-party-preferred-count-is-a-two-card-trick/story-e6frgd0x-1225910118844
Maybe a better one is some compromise, that is, to discount the second and lower preferences.

Arguably, second preference is not the same as the first preference. Then why should it be treated as the same?

I think the second preference should be treated as 50% of a preference; the third preference 25% and so on, that is, each lower order preference is discounted by 50%.

In that way lower preferences are not discarded, but they have different weights from the first preference.

That would be an improvement in the voting system.