Honestly I wouldn't be surprised if they completely screwed us but I am pretty sure it is "AFL determined" whatever that means and if they move heaven and earth to get him to GWS on a 2mil a year contract, I think they will compensate us handsomely (as they should)
So hypothetically if Buddy does go to GWS on this deal and bear in mind that we're going to be at the mercy of whatever the AFL decides, hence we have no bargaining power to elicit "overs" or really even what his truth worth in the trade market would be; What would you consider the likely compensation?
My thoughts are that based on the FA period from last year (which isn't a great sample size) clubs that lose restricted FAs are given greater compensation than similar (and even lesser) players who are unrestricted FAs. The compensation also appears not be affected by the clubs ladder position. The only other 2 factors that appear to be relevant are the age of the FA player and the size of the contract.
Goddard left for a 4 year deal at (from the speculation at the time) about $700K/year. St Kilda received a single first round pick that came directly after their original first round pick (before they traded it away) as compensation.
Assuming that is truly the maximum compensation under Free Agency then we'd definitely get that. However given Buddy would be on a contract that is essentially twice as big as Goddard's in terms of $$$/year and also slightly longer in length then it would be "fair" for us to receive about twice the compensation that St Kilda did for Goddard. So, 2x first round picks after our original 1st round pick. Given Buddy is younger than Goddard, plays a harder to fill position, has a more decorated career to date (including 2x Coleman medals, a premiership, 4x AA and club B&F in premiership year)
AND given the AFL has effectively intervened by giving GWS so many salary cap concessions then I think there should be additional compensation on top of that. So seeing how GWS would become a far improved team with Buddy I don't think they'd mind if they were bumped down to 2nd in the draft to accomodate one of our 2x first round compo picks being upgraded from 'after our 1st pick' to pick #1. Essentially leaving us with (assuming we finish 1st and Melbourne don't get a priority pick) pick #1 and the last pick of round 1 as compensation for Buddy.
ie. Assuming no priority picks or other clubs 1st round compo...
Worst case: 1st round pick after our first pick (about pick #19)
Realistic best case: 2x 1st round picks after our first pick (about pick #19 and #20)
Hopeful best case: pick #1, 1st round pick after our first pick (about pick #20)
True Value: about pick #1, #2 and #3