Well, the 'new' masts with comp-tip do seem to flex a little more and seem to give up a little energy in a hard blow. This may be a good thing.

The 'rope jib halyard' is the Aussie jib system which you guys came up with. The jib system tensions the whole rig, once set up, and on the water. The old hobie jib system had the 3:1 purchase down at the mast base. This added a heavy compression along the length of the mast. So the Aussie system moved the purchase in front of the mast to reduce compression by 66%. Cool. The downside is having all this line, a whole lot more line to deal with. Most use a little pouch to store it all. The problem you're referring to is the Dacron line stretching more than the steel cable would. Some Aussie systems are made with spectra line than will resist stretching a lot more than the stock line. However it doesn't eliminate all the elasticity and stretch. Some of the energy of a strong slap of wind might be absorbed by the rigging instead of being transferred to the boat.