Nelson is a good player, but at 33, I think he's too old for the stage the team is in. By the time they are ready for his skillset, he'll be on the wrong side of 35. Bennett is more of the age we should be looking for.
From a value perspective, Anderson a prime candidate for a good return in a trade. He had a good year and an impactful playoff series. Not sure that he should be traded because of the role he fills currently.
I'm not sold Newhook should stay or go. He's 24 but he can also slot back and forth on the 2nd and 3rd lines. He doesn't necessarily excel at anything, but doesn't have any glaring weaknesses. If he's satisfied with being primarily a 3rd liner for now, he's a great fit. He does have the potential to play himself into the 2nd line.
I'm of the opinion that if Matheson can get us a younger (under 29) 2C, or aspiring C (Savoie from Edmonton just as an example) ready to break in the NHL or a top-4 RD, he's going to be attractive for some team out there. I'd be all for trading him.
I'm not sure trading Struble is the best idea. He's not going to fetch much of a return, so it's just gutting depth on D.