Where I am coming from is our team mix in 2017.
D Pearce would be 31 going into the 2017 season, so it's conceivable that a younger player would start getting played in his winger role. Weller is the most obvious replacement, assuming he develops in line with expectations.
I'm not one of the Pearce bashers who don't see his value to the team and demand he be dropped

He has his place in the 22 currently - in 2 years that may differ
'Sell the future' was originally Purple's term in the post I quoted
All draft picks have a statistical chance of failure. All things being equal, trading 2 first round picks plus a first round picked player (Weller), for a first round picked player (McCarthy) - is stacking the game against us 3:1. There's no guarantee that McCarthy (at pick 14) is any more likely to make it than Weller (pick 13), neither do we know the potential players we are giving up in losing those two first round picks.
What I suggested is that waiting a year to get his market value down is more prudent.