I agree that it is an interesting boat. Certainly sail assist category--it has about half the sail area my Cal 46, had, weight 10,000 lbs more, Twice as much fuel--and I suspect about the same speed under power (to be practical, with twice the fuel consumption). It is certainly not a sail boat--or even a 50 50 motor sailor (where the boat will achieve good speed under both sail and power). For example 8 knots under power and sail under moderate conditions.
I also agree with the weakness pointed out. Visability is certainly one. You also loose the shoal draft of a trawler--with over 5' 9"--and 18 foot beam--huge beam--more than the average trawler this size. (16 foot beam for the Nordhavn 47). I didn't see the price--but it has to be expensive. There are already some get home sail boats--but even Beebee didn't feel that Passagemaker had adequate sail area to be practical.
Interestingly Nordhavn North Atlantic Rally would not allow a Nordhavn 46 with the Ketch rig, to participate in the crossing, because they did not feel that the sail assist was an adequate back up/vs a 27 hp wing engine. (I don't agree with that decision--but a owner sold his Ketch and bought one with the wing engine just to do the Rally.)
Nordhavn has also come out with a "motor sailor"--it will sail better.
http://www.nordhavn.com/56/overview.php
The layout has been redone so it is much more practical than initially, but still is unusual, with the foreward cockpit--eating area and galley below decks, pretty much in a cave. (initially there was no seating area below. We like the galley up on deck, along with the eating area in any boat. Both our pilot house motorsailors had the galley and main dining table in the pilothouse--al la C Dory!