First off I don't think personnel decisions are made in a vacuum and that the coaching staff is signing off on players signifying that they are a good fit for our offensive and defensive schemes.
In the case of Peters I think his underperformance has been due to being somewhat limited by injury and being placed in a lot of man to man coverage which is not his strength. We got Peters cheap and he is an established CB. Not a personnel mistake but a coaching issue.
Suh: Yes he has been a disappointment but why is that? He is on a make good type of contract with no long term exposure and all the reason in the world to perform. I question why all of the sudden he seems to be so ordinary after years of success. I have the same questions for Brockers. Is it all on the players or is there some coaching issues here too.
Joyner: He played great last year and this year he sucks. Another player with all the reason in the world to perform so he can earn a big contract and he is like a fart in church. Not sure why he stinks but he does stink.
Young linebackers: Barron hasn't played well but he is established, Littleton has played pretty good, they addressed the issue and got Fowler who has been a big plus. We mostly play 3 LB due to the depth a CB and this being a passing league.
Running back: I don't see any issues here
We are 11-2, the world works with a salary cap so you have to make choices. Talent wise I think our roster is at the very top of the league and maybe the best. I agree that we have some players underperforming on defense but I don't know if those problems can be based on personnel decisions. The LB issue is partially tied to the cap as every team has to make hard decision on where to put their cap dollars to use.
My view is that we have the players that we need to go far in the playoffs and maybe all the way. Seems like the Rams have made mostly good personnel decisions better than just about every team in the NFL better. One could argue that it is the personnel decision that got us to 11-2 like Gurley, Donald, Goff, Whitworth, Haves, Kupp, Cook, Woods, Johnson, etc. I would challenge you to name 5 NFL rosters that you would rather have.