Someone on reddit posted a composite of 20-25 draft grades and the Lions ranked 11th. I can say the ones I've looked at have been more positive: IIRC the Athletic had Lions #3, a couple others had them 4 or 5 I think.
A lot of analysts really didn't like either of the trade-up picks, particularly back into the 4th for taking Giovanni Manu. I saw more than one analyst saying they had a Free-Agent grade on him, so it's a huge reach to draft him in the third (much less trading away next year's 3rd to do so). OTOH, the guy's apparently a physical freak and we have one of the better oline coaches in the league, certainly seems like there's a chance he turns into a good player in a year or two. Seems a lot like the Martin pick from last year - psychical tools, little production, project, and we traded up significant draft capital to move up and take him several rounds ahead of where mocks had him going. We'll see where both pan out.
This thread on reddit compared what teams got/gave up in all the draft trades, and the Lions had the worst showing in terms of giving up more capital than they received, with a net of overpaying points worth a mid-3rd-rounder. However, more than half our deficit came from the Arnold trade up, where giving up a 3rd rounder to move up 5 slots at the end of the 1st round is indeed a big overpay in a vacuum. However, IMO if the Lions had traded up from 29 to say 18 with a 3rd rounder and picked Arnold, everyone would still love the pick, and now, the Lions would be showing a surplus in value on that trade. So, grain of salt etc etc.
Lastly, @Koss per your comments on not addressing oline, it seems like almost every draft analysis calls out that getting Mahogany in the 6th round was a steal; I've read over and over that people had a top-100 3rd/4th round grade on him. Now, just because most draft analysts like a guy that doesn't mean that every NFL GM kept making a mistake over and over not taking a guy, only time will tell. But it gives me a least a little more hope than normal that a 6th rounder could turn into an average starter in a year or two.
If Mahogany and Sorsdal from last year develop then o line will at least be in decent shape beyond this year. But yeah, if one or both of those guys doesn't pan out, it could all of a sudden get dicey on that unit (and I don't want to learn if Goff can play behind a bad o line better than he used to).