A shorter mast sort of complicates and makes the issues of RM worse off. By going to a shorter mast we lower the aspect ratio of the sail, making it less able to be depowered ( remember most modern sails and mast combinations are becoming more bendy in the roach and thus with powerful downhauls we can control the amount of power generation the top of the sail can produce, the A's are almost self governing now depending on batten strength etc. )and more " draggy " in higher winds.

There are also all sorts of issues with a lower AR sail also moving the centre of effort too far to the back of the boat causing tacking problems and all sorts of issues with the rudders and dagger board positions.

If anything we need to go to a higher AR sail where the uni can control the power of the sail better. One of the easiest ways would be to simply remove the lower sail limits out of the class rules, that way the sail could be made to almost come down to the deck, after all as an Uni you don't have to worry about a crew getting underneath the boom. Have a look at some of the ORMA Tris where the boom is mounted not on a tradional mast mounted gooseneck but on the deck behind the mast step.

Interesting about the Tiapan and Cobra having duals, but be aware that they are relatively old hull and sail shapes, we have moved on a bit in design and knowledge.