Yes.
It can go either way. Eg. this year Adelaide has Tyler Welsh as a f/son. He's a first-round talent, possibly top-10, but probably not top-5. So if they finish bottom 5 they get to use their first pick on another kid and match Welsh with later picks.
Marlion Jr is 14 this year. He plays at Blair Hartley's junior club. I imagine we have a pretty good idea if he is shaping to have a shot. Latrell kicked 8 goals in 15 minutes a year or two back, I imagine we're following him closely.
The gain is you know what you're getting. Look at Brisbane: knowing they were getting two gun f/son mids in the Ashcrofts, they could pick highly talented flankers Wilmot and Lohmann. They also get professional development earlier than other kids.
What way is it being diluted, out of interest?
It's a good question. He's only missed 12 games since his debut and half of those were due to suspension. So he's pretty durable. He might have a trigger clause in his contract (he did last year) that if he plays a certain number of games he gets another year. I would keep him on. We're losing a lot of experience anyway, and he won't be an old 33 (i.e. physically he'll still be up to the task). KMac goes first, for me. Plus Grimes, Prestia, maybe Dusty, maybe Bakes, maybe Graham. That's a *smile* sh!t-ton of experience as it is. (and with the team gutted this year, it's also why Marlion will get picked every week.)
As I said, Blair is in the box seat to know if it's worth getting him to 100, and is the man to decide if he'll get the chance if he doesn't get there this year.