In general, I think that policy changes should be discussed here before changes are made to the policy pages. One reason is that many newcomers will visit the policy pages to find out what the consensus is, and so the policy pages should be 'stable' (not permanently fixed, but stable, changing conservatively over time to reflect emerged consensus). We can hash things out here, and then make non-drastic changes there.
If people want to have a say in policy, the most effective tool is to subscribe to this list. This is not particularly burdensome, as a person could easily set the list to 'nomail' and read the list via the archives.
I would be supportive of the policy pages making this clear.
--Jimbo