I have learned two things from the college football "star-system" of grading. A) Fan bases love to see how their teams did.
B) Everybody loves a five-star. However, those guys are few and far between so rarely does a team grab on of those players. Generally the rankings go something like this:
5-star (100-95): A top-end player that changes an entire team. This player effects the play on every snap.
4-star (94-85): A very good player that will easily step in and be a quality starter. These players aren't going to get the huge contracts of a Larry Fitzgerald or a Calvin Johnson, but they are player that your team can lean on.
3-star (84-70): Solid prospects. Nothing special, but they won't be a hole in your team either. They generally aren't leaders or tempo-setters, but you don't have to game plan around them.
2-star (70-50): Purely a depth player.Can play in a pinch, but if he is a multi-game starter you are in trouble.
1-star (50-0) Someone who can't be trusted to start a game and should be replaced whenever you get a chance.
Now that I have set the ground rules here are how I grade out the Titans signings. These are all new additions to the team, and this system has nothing to do with how much they are getting paid.
5-star players: None
If you didn't think about contracts or guaranteed money, these two safeties would be starting from day one. George Wilson was the best defensive acquisition of the 2013 offseason. Wilson is a complete safety that has no single outstanding quality, but he is above average at everything. If the Titans decides to bench Griffin or use him only in a sub-package Wilson would be a standout FS for Tennessee.
Bernard Pollard isn't a complete player, but he isn't as far off as some believe. In Baltimore he was asked to play in the box as a true strong safety so that Ed Reed could patrol the deep middle and keep the top on the defense. Pollard thrived in that role, and not only was he a human highlight reel but he was so devastating to one team in particular that it earned him a very accurate nickname: "Bernard Pollard, Patriot Killer". A little crude, sure but it describes his play perfectly. Pollard is a true thumper and tempo-setter that could be part of a very good threesome of safeties if Griffin can play up to the potential he showed the last time he had an experienced secondary.
3-star players: Sammie Lee Hill DT (75), Ropati Pitoitua (72)
Sammie Lee Hill doesn't have a huge body of work to defend the contract that TN gave him but he does have...well a huge body. The Titans were looking to add more girth on the defensive line this offseason and they were able to lock down a very big defender who is mobile for his size. Some look at Hill's lack of playing time and think that suggests that he wasn't good enough to start, but that isn't the case. Hill rotated heavily behind two top-15 picks, and the only reason that the Lions added Fairley was because he was such a good perceived value at 13.
RP just barely made the three-star cut. He is a huge gap-plugger, but he hasn't shown an aptitude for getting to the QB despite his obvious length advantage. The reason why I like him as a three-star is because he is a chore to dig out once he is in his gap and he will look very valuable when he makes the run stop on 3rd and short and allows the defense to get off of the field.
2-star player: Moise Fokou (61)
The final player on this list, Fokou is most likely just a special teamer and depth player. I expect him to push Tim Shaw and Partick Bailey for the third ST/backup LB spot since the Titans will likely address this issue in the draft as well.
FA grade: A
Don't let the stars fool you, the Titans added three legit starters and two players with defined roles in FA this year. Pollard and Wilson will make the entire defense better both in coverage and against the run. Sammie Lee Hill and RP will be excellent run stuffers and will give the Titans quality depth in the middle as well as length to help block the opposing QB's throwing lanes. Fokou is the final piece that allows the Titans to let the draft come to them and not have to reach for a player until they feel comfortable.