[ QUOTE ]
I am not discounting importance of position but I am asking whether there's a theoretical shift in its importance throughout the tournament?

[/ QUOTE ]

IMHO, absolutely!

Many times through the tournament you are likely to go from full table to partial table and back to full again.

Let's say hypothetically that you are UTG+1 and not in the hand. 4 to your left players go all in and the biggest stack wins. Now all of the sudden, you are UTG in a 7-handed game versus the "usual" UTG in a 10-handed game.

You position is "less" important because with fewer players at the table, you can possibly play a wider range of hands from UTG, as well as play them differently.

This is just one of many possible examples IMHO.