The way I see it, the Titans have four pieces that the Titans can build around long-term. These are the players that the Titans need to become leaders of the team in the next few years and continue to develop.
1. Jurrell Casey
Casey is a known stud in both the running and passing game. He is a player that can dominate as a 5-tech in a 3-4 defense, or rush the passers as a 3-tech in a 4-3 defense, he really has no weaknesses schematically. While he isn't an elite talent like Ndamukong Suh (when he isn't suspended) he is a player that commands attention.
2. Delanie Walker
Walker is as consistent as they come when you are talking about playmakers on bad teams. Whether he is catching passes for nine yards on 3rd and eight, or taking a pass up the seam for a huge gain, Walker is a key to this offense going forward.
3. Taylor Lewan
Lewan was outstanding in his short time as a starter, so much so that I think the Titans pulled him just so that they didn't risk injuring him long term. Lewan is a tone-setter that also plays with great technique in the run and pass game, and if he can continue to grow he can become a star in the NFL (well, as much as a LT can become a star).
4. Avery Williamson
Williamson looks like what Colin McCarthy should have been a few years ago: a very good SILB. Williamson posses the strength and speed to bring down running backs in a phone booth, but he can also sniff out screens and make big plays behind the line of scrimmage. If Ray Horton is the DC for Tennessee long term, adding another DL that can eat up space so that Williamson can make the kind of impact plays he is built for.
Honorable mention: Kendall Wright
Wright didn't make this list because he seems to be sort of player with great potential, but I'm not sure that he will ever thrive in Tennessee. For every great slant TD, there is a play where he tries to make 12 cuts and then slips and falls. I would love to see Wright make the leap, but I'm not sure it will happen next year.