We're not ranked #8 on luck. This is a very good Utah team.

Next year is a different story. Utah loses a TON of players, and BYU loses very little (except in the secondary, which is probably a worry).

Utah's losses on offense:

QB Tyler Huntley. Senior starter is 495/744 (66.5%) with 6321 yards, 38 TD and 17 INT career.
RB Zack Moss. Utah's all-time leading RB has 614 carries for 3479 yards (5.7 ypc) with 34 TDs in essentially three years.
WR Simpkins. Leading the team in receiving this year, has 96 catches for 1061 yards (11.1 ypc) with 4 TDs (career).
WR Vickers. Has 14/168 this year, his only active year.
OL Paulo. LT has started 35 games on OL (missing one game the past 3 years).
OL Toala. C/G has started a couple of games this year but isn't the "starter".

Those are tough to replaces (especially Tyler and Zach). Luckily we get 4 OL starters back, but there's still going to need to be some work at QB and RB. The bigger problem is Utah's losses on defense:

DE Anae. 109 tackles, 35 TFL, 24.5 sacks in his career (so far). He's not easily replaced.
DT Fotu. 72 tackles, 16 TFL, 3.5 sacks doesn't even tell the story for a DT.
DT Penisini. 70 tackles, 13 TFL, 5 sacks career.
LB Bernard. 172 career tackles, 15.5 TFL, 2 sacks, 6 INT, 6 PBU (about 2/3 of them at Utah)
CB Johnson. 91 tackles, 3 TFL, 1 sack, 7 INT, 18 PBU. The Junior is almost certainly leaving for the NFL.
CB Nurse. 21 tackles, 2 TFL, 1 sack, 2 PBU in basically just half a year.
CB Lewis. 25 tackles, 1 INT, 7 PBU, again, in basically half of this year.
S Burgess. 81 tackles, 6 TFL, 1 INT, 8 PBU, mostly this year (played a little bit the past 3 years, but in relief)
S Blackmon. 135 tackles, 6 TFL, 8 INT, 20 PBU.

That's a lot of defensive talent to lose. Sure, Utah reloads somewhat on defense, but that's 8 starters plus a top backup (Nurse and Lewis have split the starts at CB).