In wiki questions, which are usually subjective, I want to see the most popular answer bubble to the top. But in questions that are not subjective or only have a few posts, I sort by oldest first (to see how the answers developed). On top of this, I would also like to disable the "accepted answer on top" feature, since that ruins my flow of reading the development of an answer.
Put me down as against it. Allowing this would encourage the idea that wiki means it is OK to treat SO/SF/SU as a discussion forum.
Accepted questions get special treatment to encourage the idea that these sites are for helping people to solve problems. Which is as it should be.