He is a solid younger option. I know he plays inside but value wise I just feel the Rams have enough outside now, Jack and Jones inside would make a lot of sense, Jack is also versatile enough to move outside and rush if they wanted him to. I also believe Jones is a solid rush blitz LB inside and we will see more of that next season.
I would love to see Miller and Wagner as Rams next season for a year or maybe two tops as they are both aging. Long term I believe Jack is worth the investment and would make a larger impact on the D for the next 5 years because of the overall talent level the Rams have it would allow him to really show his ability.