There's a lot to breakdown here.
Pass rush - Talent and depth will once again allow our pass rushing to be suffocating and soul-crushing.
Pass defense - One of the best coverage units at LB in the league cannot be overlooked. We have 3 LB's that cover like safeties. Sherman is another year older, but teams go after our right corner, which I think will be Moseley and Moseley has an opportunity to show he's a starting corner. We need Witherspoon to make this thing work this season, though.
Run game - Deep running back stable, excellent run blockers, and a creative run scheme that's tendency agnostic. Even without Brieda, this is one of, if not the most, difficult run games to stop in the NFL.
Short-to-intermediate passing game - We excelled in this last season and it should only get better with Aiyuk, a healthy Trent Taylor, a healthy Hurd, and a healthy McKinnon.
Health - The injury bug has been all over the 49ers since Shanahan walked through the doors. I don't know if that's a coincedence or not, but this team's single greatest obstacle is staying healthy. They can compete with any team in the NFL and have an excellent chance to win. Heath is always the downfall of this team.
Run defense - Our scheme allows for rushing lanes up the middle. It is what it is.
* I don't consider our deep passing game to be a weakness. Yes, we don't do it often, but when we do, it usually works. See below, Jimmy's deep pass completion percentage was 6th in the NFL. This isn't a staple of our passing game in 2019 mainly because of Goodwin losing his role, but when Jimmy threw it deep, he usually connected. With Aiyuk in the mix now, we could see more deep shots taken as Aiyuk was a true deep threat in college, among other things.
Yes. Emphatically, yes. Brunskill is projected to take over RG duties, which is a huge upgrade from Person. Remember, Brunskill was one of the top tackles in the league last year in both run blocking and pass blocking. According to PFF, he only allowed 2 sacks on the year and 1 penalty. His pass blocking grade was 4th among all tackles in 2019. We're getting, at worst, an above-average tackle and putting him at RG. This is a huge upgrade.
CB - Yeah, it needs to be addressed. Sherman, Witherspoon, and K Williams are all FA's. If I had to pick 1, I'd pick Williams. He's been quietly one of the best nickel defenders in the NFL. I think CB is a 1st-round target in 2021.
RG - No, unless Brunskill craps the bed, which I don't see happening. Either Brunskill takes over at LT or he stays at RG in 2021.
LT - Yeah, if we can't re-sign Williams. LT is a huge need if that happens. This would also be a 1st-round target. Assuming Brunskill sticks at RG.
DE - If Ford is a cap casualty, then yes. Even if he isn't, I'd like to see use spend a mid-round pick on an EDGE defender in 2021 at the very least.
LB - No way. Even if we somehow release Alexander in 2021 (which we will not because of the restructure of his contract this offseason), we still have Warner and Greenlaw. We don't play much base, so we don't need to invest in a LB. The Hot Boyz should all be around in 2021.
WR - Only if we let Taylor and Bourne walk, have traded or released Pettis at some point in the season, and Deebo and or Aiyuk played poorly. We've created a deep WR room, so I'm not seeing a ton of space for a FA or high draft pick unless we cleared room for it. Now, if we trimmed the group down a bit, then yes, I could see WR being a low priority need.
Needs that I see:
IOL - While I said that RG wasn't a huge priority because of Brunskill, our depth at the interior is still a problem. We have zero depth or future talent here. I like Garland a lot, I think he's a high-level run blocker, but he's terrible in the passing game. Richburg isn't going anywhere, but he can't stay healthy, Tomlinson has been very steady for us, but he's a FA in 2022. I'd like to see some young depth here to groom.
FS - Ward is not a long-term answer and the jury is still out on Moore. Even if Moore shows enough this season, I'd still like to draft a FS.
SS - Tartt is a FA after this season and will be 29 when he hits the market. I'd bring him back on a 2 year deal, but I don't want Harris being the heir apparent at SS. I'd like to see us draft a SS next year.