CEY has been great this year, you could potentially argue he's Cost Gibbs his spot. D-Mac has been perennially been the 22nd best player in the team, still has done well for himself to get to being a 200 game 10+ year player.
Douglas is better than that, club champion, maybe not a top tier premo mid but just the next step down, I think he's probably the new Scott Thompson, although CEY fits that description too.
You’re right about Milera, seems to be quickly evolving to be able to play anywhere, great half back, gun mid and can kick goals - I’m calling the Dangerfield trade a win!