Examining the 2016 versus 2017 offensive production a little further, leaving out the "hidden" defensive and special teams TDs that you referenced in your article--the production was:
2017 Offense: 366 ypg, 33 total TDs.
2016 Offense: 446 ypg, 64 total TDs.
That's a staggering dropoff that had nothing to do with those "hidden" TDs provided by the defense and special teams.
As you pointed out, we had huge scoring games in 2016 against the best 2 opponents on our schedule, PSU and Clemson, and big scoring games against VT and Duke as well, two teams that we couldn't score on last year. I think that says a lot--that we scored in bunches against our top opponents in 2016, and could barely move the ball against any half decent opponent in 2017.
Watson is going to have to be a WHOLE lot better than he was last year for the offense to be where it will need to be to have a successful season. Plenty of reason for skepticism so far.