Its very similar to the debate on here - is 2 good to very good players more value than 1 star? Tyson & Salem have both been good players, both can still improve particularly Salem so Melbourne got a good return but ultimately would they be better with 1 player, Kelly, who is better than both?
If we had the option of trading our 1st pick this & next year for Kelly its the same risk. Is it likely we would even get better than Tyson & Salem from our next 2 1st round picks???