Washington State will almost certainly be better in 2015 than 2014. How much better depends on these five guys.
I did not list any quarterbacks because the play of that position will always be the biggest key to every team's season, forever and always.
In no particular order:
1. Destiny Vaeao
With Toni Pole graduated and Xavier Cooper off to the NFL, Destiny Vaeao takes over as the leader of WSU's defensive line. Vaeao showed in the spring that he is one of the Cougars' best against the run and the pass and they'll need him to excel in both facets for the defense to take a significant step forward in 2015.
2. The punting game. OK, I cheated a bit here. But with Jordan Dascalo's decision to leave the team looming over the Cougars, they're going to have to press someone very inexperienced into service at punter. In the spring it was kicker Erik Powell, who had not punted since high school and it showed. The Cougars better find someone capable, or the defense is going to be defending some very short fields.
3. Gabe Marks
Somebody has to replace the near-1,500 receiving yards that left with Biletnikoff Award semifinalist Vince Mayle, and coach Mike Leach says that Marks has the talent to match Mayle's numbers all by himself. I tend to agree. While Marks didn't dominate in the spring game, he spent the other 14 spring practices showing that he's still the team's best receiver. He's got the best hands, runs some of the best routes and is the hardest to track down and tackle after he makes a catch.
4. Darius Lemora
The Cougars are quietly starting to build some depth at safety. While Isaac Dotson and Suli Hameed have each struggled to stay healthy, Taylor Taliulu, Shalom Luani and co. should combine to provide a baseline of solid if not spectacular safety play. Whether or not the secondary is good, however, is going to rest largely on the fifth defensive back starter: Darius Lemora. Lemora will have to be able to match up with some of the quickest opposing receivers over the middle of the field, while still contributing in the run game more than other secondary players to make for the linebacker that has been taken off the field.
5. Charleston White
Charleston White led the Pac-12 in pass breakups per game last season by a healthy margin in part because of his instincts and a little bit because of his superior speed and ability to change direction. The ridiculously long arms don't hurt, either. White was a nice cornerback in the nine games he played for the Cougars last year. Now, in his third year in the program, they need him to be a great one. Few cornerbacks can actually play on an island, but if he can force opposing quarterbacks to look away from his side of the field then everyone else on the defense's jobs become a little bit easier.