First of all in my humble opinion the J/30 has a very sweet rating in any velocity but 8-12 knots (any container would move then). We usually don't have a problem beating the J/29's, Olsons, S2's etc in less than 6-8 knots or +14 knots.
Basically I'm for changes in sailcloth even if I think it would only waste the owners money and may not help the boats that needs it the most, but if it brings more boats to the OD events it's a good thing.
As far as the 0.5 oz spinnaker a cheaper solution is to lift all "the stuff" out of the boat and put it on a scale and then leave several 100 # of stuff you don't need on the the dock. Bob Rutsch made an interesting comment about this a few years back.