Adding extra righting moment would be a trade off, the boards we use are getting smaller and smaller ( less drag ) so adding righting moment will eventually simply over power the lift generated from the boards, increase the board size and you increase the drag causing the boat to go slower.

With my weight out on the trapeze and the spinny pulled in tight on a broad reach you can really feel the boat going sideways, enough that we now take the spinny down as its faster to the next mark without it. With wings that can only be exaggerated further.

From a practical perspective the only guy who fitted wings at my club to a FX1 took them off after only a day or two as he felt the boat was slower around the course plus the leeward wing kept hitting the tops of the waves slowing dramatically the boat. What he did say is they make a great armchair and you just don't need the trapeze.