With the minimum race weights the UCI currently has, there is right now not a lot of incentive to make a road frame and fork much lighter.
Things could change though, pretty fast. Give it another two years for discs in Cyclocross and even guys like Richard Sachs will be pushed into disc brakes. They will show up in road races too, and racers will NEED them.
Discs will always be a bit heavier than rim brakes, but they are not optimized yet and the rim design to exploit the lack of need for a brake track are not yet fully exploited.
Bring in the next generation of hydraulic brakes, electronic shifting, CPU monitoring of cadence, power, and rider history... maybe even a fuzzy logic shifting bike and race frame weight will drop to provide allowance for these features and still be at the minimum weight.

The other weight adding attribute is the UCI's decrees on the measures of a bike frame and fork. Plenty of room to redesign the way one gets to the same basic contact points today, but the UCI does not want to see it. In my view they shot down the Scott Drop-in bars as they were patented, if they had been without protection they would be ubiquitous today, as one example.