This is a good one...
If we start with opportunities to improve this team I would probably say...
1) DL: You can always have another pass rusher and interior depth
2) CB: Opposite Johnson
3) WR: Big, deep threat
4) Return Man: Some one to replace Nwangwu
(NOTE: These are all players I saw play... I am sure there are others from previous years that were before my time).
DL: Jason Berryman or David Irving
The three guys I would put as options here are Jason Berryman, David Irving, and Ahtyba Rubin. Probably lean toward Berryman or Irving to add one more pass rusher.
CB: Ellis Hobbs
I would probably go Ellis Hobbs here... that would be a nice 1-2 at CB.
WR: Hakeem Butler
Purdy has improved by not having him, but if we could add a player like this to the current team (maybe one of the young guys steps up this year?) that would be incredible. From a pure numbers perspective, Brock had his best stretch with Butler on the field.
Return Man: James McMillion
The return game set us up at key moments last year (first game vs. OU, baylor comeback). We may have had 1 or 2 more losses if it was not for the incredible returns by Nwangwu last season.
(I hope that a combination of effective returns and better success kicking the ball keeps us about neutral on this one overall). Here I have to take James "The Eel" McMillion (great memories from when I was a kid growing up in Ames).
Force me to pick one... I would probably go
Jason Berryman. Give me another big, pass rusher at DE. You can never have enough.