I expect the line to be vastly improved this season, but I'm keeping my expectations tempered. There will probably be five starting O-linemen who have never played with any of the others, and none of them having ever played for the new OL coach. There's a lot of promise, but nobody has played at a blue-chip level. This is going to be a 'get to know you' season, and will likely take several games into the schedule to start gelling - I wouldn't be surprised to see the lineup change a couple of times along the way. And with so many FA signings, odds are that there will be a couple of busts.
On he upside, I see pass protection being greatly improved from Day 1, giving Allen a lot more time to throw. If all goes well. the Bills might be competing for a playoff spot. But next year, 2020, the line will be set and experienced going into the season. Then, I see Buffalo being an absolute beast. Not just a playoff team, but a threat to win multiple games.