Crosby, Malkin, Kessel and Letang are untouchable. They are all around the same age, and make up the core of the team. We will roll with them the next several years until they start falling off a cliff with age, and then we will blow it up and rebuild.
The Pens would have interest in a RHD because right now our only RHD are Letang and Schultz. Letang is injury prone, and Schultz is best when sheltered on the 3rd pair, plus isn't signed long term. We have Daley, a LHD playing on the right, where he is perfectly comfortable, but is contract expires after the season. Meanwhile, Maatta seems to be having trouble in Sullivan's fast paced system.
Ideally, we could move Maatta for a RHD of similar age and talent who fits our system a little better. Hamilton could do that, Trouba could do that etc. Meanwhile Pouliot is still developing and will hopefully fill that Maatta hole in time.
Long term:
Dumoulin - Letang
Pouliot - RHD Trade for Maatta
Cole - Schultz
As suggested in other threads, Maatta + Fleury for Hamilton + Elliot, with picks or other minor player adds as necessary, would work for us.