Outside of anonymous online posters, every person I know who knows football (either from playing collegiate and beyond or coaching) has praised the offensive line this season (other than the UMass cluster).

See, for example:
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For whatever reason, this team hasn't been united all season. Talking to players, I have been bluntly told that they don't feel there is unity, there isn't a leader, etc. ...
And all that comes down to the head coach. I don't know what it was he did that lead to the dischord, but the team was not united.

I hope he can fix it next year.

Football is [probably] the ultimate team sport. One guy (almost never) wins or loses a game. Sure one guy, a kicker, can snatch victory from the jaws of defeat (or vice versa) with one kick at time runs out ... but the truth is that it was the team that put them in that position. Typically the O hasn't put up enough points, or the D gave up too many. I can't think of any instance in which both O and D played well, and it came down to a kick to save the game.

So, in answer to your question, the O-line did many things good this year. They had some key break-downs though ... penalties always hurt, and sometimes are crucial; giving up sacks kills drives; QB hurries (even when it is just that the QB feels some pressure and so doesn't check through all his progressions) hurt. Sometimes it is that the QB, the RB, the coach, doesn't have confidence in the line to do a certain job and that affects play calling, running, etc.

sometimes it is that the O-line doesn't have the confidence in the back, QB, coach, team, and that results in lack-luster play.

For whatever reason, this team hasn't been united all season. Talking to players, I have been bluntly told that they don't feel there is unity, there isn't a leader, etc. These things reflect differently on different position groups: receivers who aren't confident in the QB or the play-calling, run soft routes, and don't fight for the ball; O-line makes mistakes, don't hold a block as well, etc; QB's get happy feet, over/under throw, etc; etc.

I saw the O-line make some bad mistakes. I also saw them play some good ball. The biggest problem that I saw was that the TEAM wasn't ever "in synch" ... they lacked the leader who would/could guide them through the trouble spots and carry them home. D had Fred Warner ... and the D didn't gel around him ... too much turmoil. O never had a real leader.

And all that comes down to the head coach. I don't know what it was he did that lead to the dischord, but the team was not united.

I hope he can fix it next year.

All of these problems can be explained by the astoundingly poor play of the offensive line. Even the loss to UMass can be hung on key penalties made by the big men. So was that Ty's fault? Perhaps because Ty neglected to beat down on Mike Empey (everyone knows that Ty is a classy guy who doesn't do that sort of thing).

The team hadn't given up many sacks this year, until the UMass game.