The NT700V is really a 55 hp bike and is somewhat of a vibrator at speed. By the time you calculate the hp/weight ratio and compare fuel efficiency it's much different in range and performance than that of the NC700X but all the other positive attributes are accurate.Depends....
What is your inseam? How much do you weigh all geared up? The wife?
The NC has about the same wheel base as your PC does but will probably be more crowded. The PC800 might seem like a comfy Lazy Boy compared to the relatively cramped NC, especially if you end up with panniers (takes away passenger leg room) and a top box. My daughter is about 5'7" and 130lbs and with the panniers and top box on we are pretty tight...to the point of banging helmets once in awhile. The passenger seat is about the size of a dinner plate.
Seat height and comfort are a consideration to many. See the numerous threads on lowering the bike and improving the seat if either might be an issue.
Compared to the PC the NC will have zero in the way of wind management and of course other than the funk, there is no storage.
The fuel tank on the NC holds less than 4 gallons. Not an issue if you ride like grandma, but on a highway you can hit reserve in as little as 150 miles. That isn't an issue to a lot of riders, since well, NC riders aren't usually in a great hurry and if you baby it, 200 mile range is doable. This forum leads all other M/C forums on the planet with the number of Fuelly links in member's signatures. We are a frugal bunch ;-)
The chain/sprocket maintenance might be something that you grow to despise after coming off a shaft drive. Others find it a soothing way to bond with their machine. Or something.
A 670cc DCT weighs over 500 lbs wet and has about 45 hp or so....toss in a rider/passenger/ full tanks/panniers and well, you get the idea ;-) Since your PC isn't exactly a barn burner in the HP department either, that probably won't bother you too much, especially if most of your riding is solo.
These motorcycles are so inexpensive used, that if you are serious you could probably pick one up, try it for a summer or so and if it doesn't work for you, sell it for a few hundred less than you paid.
EDIT: You might want to check out the NT700V instead. It is the modern version of your PC800. Built in panniers, shaft drive, nice size fuel tank that carries over 5 gallons, ABS, 65hp, they have a lot going for them. Including 565 lbs of road-hugging weight ;-)