The rig has been criticized, though never by anyone who's actually sailed the boat. Armchair observers of the published sail plan complained that the sail was too small, the boom too high, and the peak too low.
First, as to size, it's important to remember how light the Skerry is: only 95 pounds, 30 pounds less than a Laser dinghy. There are kayaks that weigh that much. The loaded hull sits on a waterplane that measures 12'3" x 3'6", a skinny, easily-driven shape. 56 square feet of sail works out to a sail area-displacement ratio similar to a Laser. The Skerry jumps right up to hull speed if there's any wind at all, and when the whitecaps are up, the crew doesn't have to exhaust themselves keeping the Skerry upright. As a casual day sailer, this is desirable. The lower peak echoes the shapes of the classic faering sails, and for the same reason: it keeps the center of effort low and the spars short.
I set the boom up high so that the boat can be rowed when the sail is set. This has been a universally praised attribute of the Skerry. The ability to jump to the oars to maneuver away from shore or around an obstacle is critical, I believe. In many small boats, the rig clutters the boat up so badly that you can't row when you really need to.