here's my tentative draft philosophy on Defensive Tackles.
Thanks for explaining your philosophy in such detail and I agree Grid is awesome.
For me in no particular order.
1. Size, speed and athletic ability.
2. Do you get low and play with good leverage.
3. How are your hand skills.
4. Can you play multiple roles.
5. Do you have a skill that is dominant.
6. What type of gap player are you.
7. Do you play with power and are you physical.
Steph Tuitt has good size but his speed is marginal as is his athletic ability. He plays with decent leverage. His hand skills need improvement especially as a pass rusher. He can play multiple roles. I don't feel he has a dominant skill. He's a good run defender who could become elite in that regard with better power and hand skills. He can play a one or two gap but is much better suited to a read and react two gap. He plays with decent power but it could be improved.
I then match up prospects based on how I feel they are in different roles. A guy like Nix can move way up because he requires multiple blockers and could be dominant. I think Vollmer would handle Tuitt all day one on one.
You have to deduct some points from a guy like Donald because he lacks size, lacks are length, if he gets a good initial burst he plays with good leverage however if he doesn't then he loses leverage and isn't effective.
It's complicated but I try to picture how they fit in the defense and how they would matchup vs different players in different situations. I simply can see either TJ or AD playing along Chris Jones on passing downs and making a difference by getting up field. I was mulling over your suggestion of having Donald playing DE in the 4-3 on early downs and kicking inside on later downs. I have to go back and see if I think he can effectively set the edge on a consistent basis. If he could do that I would elevate his stock.