You could make the argument that JT Miller is a Matt Duchene equivalent but two years younger with more years of RFA control. He's yet to have a 70 point season like Duchene has, but he could be trending that way. So just for the sake of argument, let's look at what Duchene returned:
Defenseman prospect
Samuel Girard, Nashville’s 2016 second-round pick
Forward prospect
Vladislav Kamenev, Nashville’s 2014 second-round pick
Forward prospect Shane Bowers, Ottawa’s 2017 first-round pick
Goaltender Andrew Hammond
2018 first-round pick from Ottawa*
2018 second-round pick from Nashville
2019 third-round pick from Ottawa
1st, 2nd, 3rd, 3 prospects and a cap dump goalie
2 1sts, 2 2nds, a 50 pt RHS D man and you are sending the cap dump, not the other way around, is too much.
I'm not sure if I'm GMJR I would do this, but based on the above a market rate deal would be more like:
Pen's 2018 1st
Pens 2018 2nd
Pens 2019 3rd
Tristan Jarry
Andrey Pedan
Teddy Bleuger
Carl Hagelin
The above seems like way too much though, which is probably why the Pens, despite being very interested in Duchene, did not ultimately land him.