Pesce and Hamilton are both over 30. You don't trade a 20 year old 2nd overall pick because of guys like that.
Hamilton won't finish his contract as a Devil. I would be shocked if he did.
Hamilton is only 31 with an NMC and 3 years left at $9M after this season. He's still providing elite level offense and was one of the biggest FA signings in recent memory for the Devils. Unless he starts having injury issues and goes the LTIR route he's finishing that contract.
Pesce just turned 30 and just signed a 6 year FA contract less than 5 months ago. Casey is NHL ready and killing it in the AHL, Kovacevic has been great and could be a potential re-sign candidate.
I'm also not saying to trade Nemec away for some older player, I'm saying if a scenario arises where a team has a similarly talented blue chip forward, it would make sense do to a logjam at RD vs a forward group that is shallow after the top 6.
If there's no team willing or able to make that trade then the Devils just hold onto Nemec and Casey and deal with a good problem in having too many talented defensemen.