Should NDSU go FBS, no in my mind. There is more than just the FB coaches salaries going up. Correct that more seating would be required. If NDSU becomes FBS then all salaries go up from the President on down to every instructor. Don't believe that, check what happened when they went from Division 2 to ! and the FCS.
Recruiting becomes more difficult for reasons stated above. Raising more money has it's limits. Currently raising money in a city of 100,000 and a state of 6-700,000. A lot of FBS schools have our state population in the city they are located or at least very close to a major population. Would the support be there with a continuous 6-4 record or even a 9-2 record and qualifying for a no-name bowl game sometime between Christmas New Years? Most big name bowl games come from major conferences, not they smaller conferences. Remember a few years ago when Boise State was undefeated most years for much of the season and rarely broke into the top 10 unless they were the only undefeated team left in the country.
Perhaps the best is now. There is no shame in making the rest of the country chase you instead of always chasing them. What's the old saying "unless you're the lead dog in the pack, the view is all the same."? Don't think for a minute that staying on top is easy, might be more difficult than getting there. NDSU never plays a game without a target on it's back.
Go Bison