Probably the biggest key is how much the OL improves. If they're as good as the coaches say they're going to be, meaning they can run block, then the offense will be more effective than last year. Not more explosive, but more effective in the sense of being able to control the ball and grind out a few yards at crunch time. Better ball control, just being able to grind out another 4 or 5 first downs in the 2nd half, would have really helped them against teams like Iowa and Ohio State and MSU.
One thing Barkley did last year was make it easy to put together a defensive gameplan against PSU. You had no choice. But this year defenses will be more focused on containing McSorley initially. And then after a few games, hopefully, they'll have to worry about Sanders and the new receivers.
I'm pretty confident in the pass blocking ability of this line -- they did extremely well toward the end of the year when Bates got back. And we saw flashes in the bowl game of what kind of run blocking they might be doing this year with Gonzo and Bates and McGovern all flying around. The other big test for the OL is the depth. They will probably lose some people to injuries for some games against top 10 opponents. A top 10 team has the depth to deal with the loss of a Bates -- last year PSU didn't, but maybe this year.
One thing to watch at is that McSorley does not look as comfortable as a pocket passer as he is as an improviser. This OL puts a wall around him, that may not actually help him. Hopefully they will still try to split the center of the D so that McSorley can step up because that plays to his strength.