Is a restricted class of boats what the sailors want or what the organizers want? Customer focus will be really important for this to work - most OD classes have seen declines since the last days of the Worrell. There is probably a very short list of people that have the time, resources, and desire to do a catamaran based Worrell race and I would identify who those are FIRST (assuming you haven't already) and figure out what format they would prefer. A lot of events lose site of the reality that the sailor/competitor is the customer and the race organizers are selling a product to the sailors. The pool of willing sailors is much smaller than it was 10/20 years ago so the product HAS to be precisely targeted. You also can't necessarily rely on what's been done in the past.

Some out of the box thinking may provide some results too. The only adventure style races that are growing are the Watertribe style events and the R2AK. Food for thought.