Who plays and whom does not is a huge topic that could go on all year. I have a way of looking at it.
1. We only have 63 scholarships equivalents, so we should not have Fr., So., Jr. & Sr. at every position. That means you have non-scholarship guys (usually minor abilities) or your coach really cheats. So I would expect to see 2 to 3 years between position/player classes. That being said, the odds of an underclassmen being a better player that an upperclassmen should be very rare.
2. "Better" vs. "Ability": Just because a young player has more ability than a more experienced player, does not make him a better player. This where your coaching comes into play and was coach Wolf's BIGGEST problem. Not to open any wounds, but when I saw Moore take a few snaps at TB, I knew right away that he was something special. Yet, I said, let's RS that guy, as we had 3 solid backs. One graduating in 2-years & the others graduating in 3-years. This year is the final year for Ruiz and Webb, with Hymes graduating last year.
3. Earning your spot. If I earn my spot I expect to keep it. There better be some substantial differences in performance for a younger player to step over an experienced player.
-As a Frosh: I should expect to practice with the team & maybe see some reps.
-As a Soph: I should have a Senior in front of me (if my coach recruits well) and I should expect to to see more reps, but the senior is going to start.
-As a Junior: I am the starter if my coach recruited well. If there is a Senior, it is probably either (a medical situation) where the senior should start if he is healthy, or he is a true student athlete (more brains than player) ...so either way I am going to see substantial playing time, if not the majority.
-As a senior: If I played my cards right & I am healthy; I should be playing the best ball of my life and the coach DOES owe me that starting spot. Coaches better realize this, as they will be losing players (at all classes) and recruits if they get a reputation of not rewarding the contributors.