I would agree with this. LT has to be a priority, and they need a starter. Lowe can be a back-up and could play if someone was out a week or two. Season-ending would be brutal, but it's obviously impossible to have that kind of quality depth (2 high-end LTs on the same roster).
Wallace is the X-factor at RT. His injury was tough but he's potentially their option on that side. I don't recall him being terrible on the RT, but he definitely struggled on the left. Although, I've said it before, I think they hoped he could be developed as a left tackle. I don't think the plan was for him to be the starter that early in the season. The Okorafor thing blew everything up and really created a lot of the problems. He wasn't their long-term answer by any means, but I'm sure the hope was that they could get through this season and address it next offseason.
A top WR I do believe would change things. They need a guy who draws attention, especially on the boundary, which creates opportunities for these other guys. They don't have anyone right now who demands additional attention from a safety, and I feel like that's part of the reason there are so many plays where guys aren't open. They don't have a one and/or a high two, just a group of 2s (barely), 3s, and 4s.
Those two things alone would increase the scoring. I do feel the roster is adequate on defense, albeit another CB and interior lineman would be nice. When I say "adequate" I mean for this season, and I do believe the real-time ability to assess the opposing offense and adjust by the current coaching staff is an issue.
That's an area where I'm not sure if Covington has the ability for the job. He's clearly a good position coach and a smart defensive mind, but seeing it in real-time rather than in a closed-setting on film are two different things. Mayo doesn't appear to either, and I think he needs to surround himself with someone who is better at that. Because that would absolutely be an issue in a big game, and Sunday's game against Miami was a giant red flag when it came to that. At least in my opinion.
Granted, it would be nice to see some additional depth all around, but I agree with
@mgteich - that would be the minimum I'd want to see.