I upvoted your post because of the bolded and I think even a top version of Walton isn't a great value pick in R2 as has been tossed around by some. Take a look at the data, show me guys with Walton's projected peak testing numbers (which may not even be possible now because of injury) and maybe we can see a reference point. The ones I see are closer to R4-R5.
I only went back to 2014, but these are some Day 2 picks with similar measurables to what I expect from Walton:
Duke Johnson- 5’9, 207- 4.54
Ameer Abdullah- 5’9, 205- 4.60
Kareem Hunt- 5’10, 216- 4.62
Tre Mason- 5'8, 207- 4.50
Bishop Sankey- 5'9, 209- 4.49
Don't know how Walton's other numbers stack up (shuttle, VJ), but I've heard from defensive players that he's the best pure athlete on the team.
In 3 of the past 4 years, there were 8 RBs picked in the first three rounds. The big issue Walton is facing is that it's an exceptionally deep group of RBs. That, coupled with the injury, could push him down if a few guys go pro. But I think in the normal course of business he is a Day 2 player.