If he came cheap, I'd add him. The list you have has become stagnant, or complacent. A new threat would perhaps show us something new in those players.
I think this is where we disagree. My thoughts on the players mentioned:
Cordy: Has a good future; great pace and agility for a big guy and a strong mark. Has had his early career affected by injury so is taking a bit longer to develop. Can definitely see him as a FF.
Roughead: Has definitely not stagnated. Showed a heap in defense this year, and is still a pretty good backup ruckman, if needed.
Minson: Not much needs to be said; still improving and is the present.
Campbell: Hasn't shown a heap in the forward line as yet, but it's his first year and he definitely improved. Showed a heap in the ruck; I have no doubts he's a future #1 ruckman.
Panos: Probably has stagnated a bit, not going to deny that.
Hill: Is still steadily improving. I can see him having somewhat of a future in AFL, but probably not in the league of some of the others mentioned.
Redpath: Haven't seen enough; first year + injuries.
Jones: Had a bad year, but still has a lot of potential. See him as more of a CHF, though. Can backup ruck if needed.
Skinner: Showed massive amounts of improvement in each match he played. Still confident he can become a decent player, and his third-man-up abilities in the ruck are great.