First, many on here, and I'm one, never trusted the coaches even last year. We won in spite of them, not because. Dak was otherwordly and Zeke was MVP quality. At critical points, either the opposing QB would suck it up or the defense would make a play. I think we forget a little that some of last year's success was due to the former.
DL is not all around better. DLaw is balling out and the pressure is better, but the line has been atrocious against the run, and that has killed us so far. When you're averaging allowing 6 ypc on first down, anything you can do against the pass is somewhat diminished.
Brown is not better this year than last, at least not yet. Can he be? Sure, but he hasn't played these first 5 games as well as he played the last 5 last year.
You are right that IF everyone plays we'd be ok at LB. But that hasn't happened yet, and with Jaylon's travails we are significantly worse this year than last at LB. We can hope for the best but we're razor thin.
Heath (or Woods) so far this year has been significantly worse than Church, even though I don't think Church is more than JAG. Again, we can hope this improves and it very well may, but to this point safety has been another major downgrade.