I fully support this change. That's actually the way I use the flag right now. Anything I dislike I will downvote, and no matter what the 'flag' says when I click on it, I can click it whenever I want.
I also believe the downvote should be part of the curation algorithm. Users who downvote should have more power on their upvotes. A typical user should have about a 80% upvote/downvote ratio as is the case on reddit (a finely tuned website that regularly pushes good content to the front page).
support... the word 'flag' is somehow discouraging people from using their downvotes.
switch back to the more neutral 'downvote' wording could drive the community back to a more healthy up/down ratio.