I disagree. Vote locking was introduced to prevent tactical downvoting — where you downvote a competing answer immediately so that it gets "pushed" below yours in the sorting and then remove the downvote when you're sufficiently ahead. Tactical downvoting is still a problem on SO and implementing this change would put the power of tactical downvoting in the hands of the very few that are above 20k, greatly worsening the problem.
There are often legitimate reasons to reverse a vote as new information or understanding comes to light, and I should not have to edit the answer just to unlock my vote
If there are legitimate reasons to reverse a downvote, then just ask the answerer to make an edit so that you can change your vote. I'm sure they'd be happy to oblige. If you'd like to reverse an upvote, then make the edit and remove it and let them know why you've removed so that they can make the necessary changes to get back that upvote. If you'd like to be discreet about it, make the edit and come back a few days later to reverse your upvote.
"Trusted user" is often misunderstood by many to mean "we trust you to not to indulge in bad behaviour, so here are some relaxed rules for you". It might help to sit back and take a pragmatic look at it and realize that all it ever means is "good job, here are some more tools to clean up the muck!".