I don't think the midfield rookies run as deep as most people think, to be honest.
You have your Wines, O'Meara, Viney and Crouch that are locks that everyone will have. And then you can splash out a lot of cash to get Whitfield, Hill or Toumpas (who all have question marks anyway). But it gets a little hazey after that.
K.Mitchell: I don't think he's the lock that everyone thinks he is. He mentioned in an episode of DT Talk earlier in the pre-season that he's been training as a lockdown HFF. While he was allowed to run free in the first few rounds of the NAB Cup, last night vs. West Coast he played a defensive role on Shannon Hurn and only picked up 3 disposals from 69% gametime. Then you add in that he's a shocking kick of the football and isn't a best 22 lock anyway... he has question marks on him.
D.Kent and M.Jones: The Melbourne boys have both been impressive in the NAB but can you really trust their job security and roles? Melbourne have quite a few mids that are similar to these blokes (Magner, Couch, McKenzie). They are boarderline Best 22 at best. Still not sold on either of them, though they are very cheap.
J.Lonergan: Should see plenty game time this year but probably won't be a prolific scorer. He's 23-30k more expensive than most rookies too so you have to ask yourself if he's worth that. Showed a bit in the NAB but not enough to lock him in.
Then there's guys like Colqhuon (or however you bloody spell him name; looks a player, but is still very skinny and probably won't get games right away), Tom Mitchell (won't play right away), Kavanagh (won't play right away), Kommer (might get a shot Round 1 but will most likely play as a defensive forward and probably won't score too well), Anderson (could get games from the start but will likely wear the green vest a lot), Blicavs (smokie; could play early with the injuries that Geelong have but probably won't score too well).
Of course you could always just chuck guys like Vlaustin, Goodes and Neade into your midfield if your finding mid rooks hard to come by.
It'll be interesting to see how many and which rooks people end up going with in the mids.