you have offered very good analysis on other trades, I do not see that here.
Buffalo is clearly giving up the best 2 players in the trade Dahlin and Eichel while Duchene and Arvidsson are the best two players coming back IMO they do not measure up to what Nashville is getting.
Eichel over Duchene
Dahlin over Arvidsson
I would rather have Reinhart over Granlund (this is close either way, I am taking Reinhart because he is 4 years younger)
Ristolainen over Bonino, Say what one will about Ristolainen, he is 7 years younger, and has 41 more pts than Bonino over the last 4 years.
Mittelstadt over Hamhuis (this is a no brainer youth and skill heavily favors the Sabres) the Sabres do not need another 7th defenseman
Luukkonen is not as good as Rinne but he is 36 and hopefully in 2 years UPL will be the Sabres #1 GK and by then Rinne will be retired.
This is my analysis of the trade, I would like to hear your breakdown, maybe I am too much of a home town boy, but this just looks really bad for Buffalo.