I was close in my final roster project a couple weeks ago.
In my projection after preseason game 2, the only guys I had making it who didn't are CB Campbell (injured), S Webb (injured), and Edge Davis. I think both Campbell and Webb would have made it if healthy. I'm disappointed about Davis and hope he makes the practice squad.
The guys who made it that I didn't project are RB Rountree, LB Ogbongbemiga, and CB Leonard.
I can understand Ogbongbemiga. The team seemingly made the choice to use Van Noy as the 4th Edge player, which implies fewer snaps for him at ILB. Not sure I agree with that, but I understand it was a decision point. (I think using KVN at ILB1 exclusively while using a player like Jamal Davis for Edge 4 snaps arguably maximizes positive impact on the defense... but I also fully expect KVN to be a quality Edge player...)
I can also understand Leonard, though I doubt he would have made it if at least one of Campbell or Webb were healthy, and it seems possible that he will be dropped to the practice squad as soon as Jackson is recovered and playing normal snaps.
I have no idea what the team sees in Rountree, and I see no reason for them to be concerned that he would have been claimed on waivers, so he almost certainly would have made it to the practice squad. Supposedly, his value is on special teams, but that implies that he has to be active on gameday. I could see that in the first week or two if Spiller's ankle leads him to be inactive, but I can't see 4 RBs and FB Horvath all being active on gameday, and Rountree is the obvious man out if all are healthy.
Bottom line, I think this is the roster of a championship contender if they stay healthy.