Starters Comparison
Pos - 2018 - 2019 - Verdict
DE - Wise - Wise - Slight upgrade, because of experience
DT - Guy - Guy - No change, added experience countered by more mileage on the tires
DT - M.Brown - Pennel - Slight upgrade, as Brown was a bit of a disappointment
DE - Flowers - Bennett - Slight downgrade, though it's very close
LB - Hightower - Hightower - No change, assuming good health
LB - Van Noy - Van Noy - No change
LB - Roberts - Roberts - Slight upgrade, because of experience
CB - Gilmore - Gilmore - No change, all-pro player in his prime
S - Chung - Chung - Slight downgrade, as he's getting older
S - D.McCourty - D.McCourty - Slight downgrade, as he's getting older
CB - J.McCourty - J.McCourty - Slight downgrade, as he's getting older
Reserves
Pos - 2018 - 2019 - Verdict
DL - Butler - Butler - Slight upgrade, because of experience
DL - Grissom - Winovich - Major upgrade, on talent and motor
DL - Shelton - Parry - No change, hard to see one being better than the other
DL - Simon - Simon - No change
DL - Rivers - Rivers - Slight upgrade, because of experience
DL - Davis - Davis - Slight upgrade, because of experience
DL - Kamalu - Cowart - No idea
D - Grigsby - Calhoun - No idea
LB - King - King - No change
LB - Bentley (IR) - Bentley - Major upgrade, assuming good health
LB - Sam - Sam - Slight upgrade, assuming good health
CB - Rowe - Williams - Major upgrade, as Rowe just wasn't great and Williams can be
CB - Crossen - Crossen - Slight upgrade, because of experience
CB - J.Jones - J.Jones - Slight upgrade, because of experience
CB - Dawson (IR) - Dawson - Slight upgrade, assuming good health
S - Harmon - Harmon - Slight downgrade, as he's getting older
S - Melifonwu - Melifonwu - Slight upgrade, because of experience
You can see that basically I assume that if you're on the front end of the curve (i.e., before you reach your peak), you'll improve with experience, but if you're on the back end of the curve, you'll decline due to age and mileage. Someone like Guy is right at that point where the two probably counter each other. I assume that people like Bentley and Dawson will represent upgrades if only because they would be healthy, and a healthy Bentley is better than Bentley on IR. A few spots, I have no way of knowing or even really guessing.
Obviously I'm spitballing here, but I see:
3 major upgrades
11 minor upgrades
5 minor downgrades
0 major downgrades
8 no changes
2 no ideas
That to me would represent a pretty significant cumulative improvement from 2018 to 2019. Of course, who knows really, and injuries could play a big factor and such. But I think they have a chance to be very good on D, *especially* if Bennett still has enough in the tank and Winovich is the real deal.