I agree with you. Matthews has value but he's not going to come in and have 8-10 sacks. Considering he'll also play some ILB 4 would be great...
Like you said, between Fowler, Matthews, Obo, Ebukam, Fox, and maybe UDFAs they simply need to produce as a group. 23.5 sacks off the edge in 2017 became 6 in 2018. Can they split the difference and produce 15 in 2019? That plus a more consistent secondary would do it...