I find it a bit annoying which answers get the votes on SO. A practical answer to a practical problem, especially in a niche or relatively advanced topic, gets very few votes no matter how good. An opinion about a general topic gets many more votes.
I stand by my top two vote-earning answers, but they definitely reflect this tendency. I think I have written much more deserving and much more useful answers.
So - I'd like the ability to transfer votes from one answer to another.
Common sense applies, of course - limits based on proportion etc should be included, moderators should be able to reverse my decisions (or delete the transferred votes) and perhaps ban me from doing this in the future if I abuse it, it should only be possible after I cross a certain reputation threshold, and votes should only be transferrable once (no shifting votes around as a quick con to get answers accepted by deception). Maybe there should be a reputation cost as a disincentive to abuse.
But - used appropriately - it's a simple way that contributers who've earned the reputation can use that to highlight the answers they think are most useful, rather than those that attract the attention of the masses.