Fremantle needed to add to Darcy for the same reason Richmond needed to add to Nankervis. If you think Richmond needed to add to their ruck stocks (and you have) then Fremantle needed to do the same.As for Fremantle drafting depth ruckmen late. The national draft is about targeting players who can improve your best 22. Sean Darcy projects as Fremantle's clear number one ruckman going forward. If you want injury cover and depth, that's what the rookie draft is for.
Plus, I know Sandilands is still on the list, but he's not getting any better. He's nearly 35 and just did his hamstring twice, which isn't ideal.