If any of these is a starter, we are weaker at that position.
I really see no issue with the DL.
2018:
DE: Flowers(70%), Wise, (41%), Clayborn (30.5%) Simon (18%)
DT: Guy (50%), Brown (44%), Butler (36%), Shelton (31%)
Davis had some snaps too but by the end of the year Simon had taken that spot.
They lost Flowers, Clayborn, Brown and Shelton so they need to replace those snaps. IMO Bennett can fill Flowers role well and be the leading DE and DL man on the team. He played 69% of the snaps last year and is use to carrying the load.
Flowers is a very good player but so is Bennett. As for losing Clayborn I honestly don't think they will miss him much. While I am not high on Simon by the end of the year he was clearly out playing him. Even if he regresses a little this year I still think they are better off with him than Clayborn. They will need to pick up another depth DE but it isn't a bad line up.
As for DT Shelton and Brown were merely run stuffers and frankly weren't that good at it. Shelton in particular was disappointing. IMO Butler is clearly a better player than both but simply has a different role. Guy was one of the better DTs in the NFL last year all things considering. Mike Pennel is a better big DT than either. They do need another big body but those can be had in the draft. IMO Pennell + JAG > Brown + Shelton. I'll already call it an upgrade.