Will Fries has never played a snap of college football, so you're just gonna throw him out there ahead of a healthy Mahon or Bates? Both of whom were highly effective at left tackle a year ago, and Bates especially is just tapping his potential as a now redshirt sophomore. I know for a fact the staff loves Bates potential at tackle.
Brandon Polk needs to prove he can stay healthy. Until then, he's an unknown that runs fast. As you said, Blacknall has a ton of potential, but needs to put it all together. I think he was really set back by his hand injury last year, and missing those 4 games early. Irvin Charles and Juwan Johnson will take on bigger roles, and Hamilton would benefit from a move back outside instead of the slot. He was better there last year when he rotated in with injuries. Gesicki is a huge x-factor in the passing game as well, obviously. He's essentially another slot receiver that is a matchup nightmare.
This idea of a "blocking tight end" is great, but I'm not sure Moorhead's offense necessarily needs a guy that is primarily a blocker. A healthy Nick Bowers would be a huge help though.
The offense can certainly challenge the entire field, but a huge part of the "all or nothing" offense of a year ago was what they were given. Teams really sold out to stop Barkley, with good reason, and it created all sorts of 1-on-1 mismatches down field. If the 40 yard pass is there, you take it.
My personal feeling is a lot of the improvement you're looking for comes from guys getting another year's experience, especially up front. We were exceptionally young at a lot of spots, and a year of playing time, plus another year of time in the weight room, will really benefit everyone.