Explain to me why this defense won't be the worst in NFL History

[Picksix]

Last year's defensive accomplishments:
-32nd in yards allowed/game
-32nd in first downs allowed/game
-T-31st in penalties
-29th in 3rd down % allowed
-27th in points allowed/game

So what does the front office do to improve last year's abysmal unit:

a) Sign Henry Melton to replace Jason Hatcher, who was the best player on defense last season. Hatcher was dominant rushing the passer. Best case scenario is Melton returns to pre-injury form and replicates what Hatcher did. Not saying I disagree with the move of letting Hatcher go since he was commanding a lot of $ for a guy on the wrong side of 30, but this is a lateral move AT BEST.

b) Draft Demarcus Lawrence to replace Ware. We'll be lucky if he gives us George Selvie production his rookie season.

c) Reached for Anthony Hitchens. I'll give the front office a little slack since Sean Lee didn't look like anything special in his college YouTube highlights as well, but trading for Rolando McClain doesn't exactly give me confidence in this pick.

Those moves basically add up to last year's defense again, at best. Unless we're counting on Bust Carter, JJ Wil-whiff and Pourous Claiburnt to make huge leaps.

If Lawrence gives us what Selvie did last year, it will better than what Ware did. That said, there are some reasons for hope. Players coming off injury, and the idea that it's very unlikely we'll have to play 17 different DL (with Nick Hayden having 800 snaps). I think McClain will be a significant upgrade at the 1 tech. Claiborne hasn't been healthy his first two years. But he is now. IF he can stay healthy, and the CB's are allowed to play more man instead of zone, there should be improvement there. It's the second year of the system, and teams employing this scheme typically improve in the second year.

Don't know if any of this comes to fruition. They may very well be just as bad as last year, if not worse. Just offering up some reasons for hope.