Well perhaps he was lacking match fitness but he seems more the stay at home contested-mark FF, lacking a certain agility to run and lead up the ground - like the qualities I mentioned Hendo seemed to possess.Not sure what you mean about Casboult not being a good mover, he was good up the ground this year and good around the ground as a ruckman. His up the ground game against Essendon was excellent. Not bad for a guy who came into the AFL after a massive lay off.
Well I thought Macca, from his experience as a defender, looked more of a natural in terms of knowing how to present and position his body. Walker's as a midfielder makes him rely more on his athleticism.Besides that's less important for the up the ground role you are suggesting which makes Walker a great candidate.
McInness is not a key position player, he would always be the underdog and under sized playing key position.
I don't know why you'd think Walker would be more suitable as a lead-up target than Henderson or McInness when his trademark, when not in the midfield, is as a high flying goalsneak deep in attack?
This is not to denigrate the abilities of Levi nor Walks but emphasise that Henderson and McInness can and have played successfully across half forward.