I would wait because alot of the players you have are only starting to heat up after dismal starts. IT can only get better.
You have enough dual categories forwards to only roll with 3 D. IMO if your D aren't producing, and you can't find a better one off FA, just roll with more forwards. With proper planning you may only lose a few man-games and in the end it will be worth it because your forward will still outproduce D.
Alternatively, if your D aren't doing anything, try to pick up a D only to win certain categories. Ie - search for the top ranked D at +/-, PIMs, SOG, etc. This will ensure you at least win that category.