At the end of the day I can think of lots of examples of disgruntled (openly or not) players who were eventually moved just in recent history...Nash, O’Reilly, Duchene, Trouba, PLD, Laine.
I can’t think of many who mended fences with their current team. If it is true that Eichel wants out, IMO it’s an if not when situation. We don’t really know enough to know what the real situation is behind the scenes.
Again if I am Buffalo I'm just keeping Eichel unless the trade brings back way more than is seemingly going to be offered for him.
If he asks out, even publicly, I just say I am still working on a trade.
ROR did not want to be in Colorado, he was traded, the return did nothing much for Colorado. Then he did not want to be in Buffalo, the return for him there also did nothing for them.
Nash, did the return for him really help Columbus more than Nash himself playing there would have? In fact the Rangers won that deal based not only on Nash but the 3rd they received back turned into Buch.
Duchene much like ROR was traded twice and the total return amounted to Turris.
It just does not make much sense for teams to trade players when they request a trade. Trouba wouldn't sign away any UFA years, maybe lucky for the Jets, however Eichel is signed for 5 more years, not sure how that is an apt comparison.
Buffalo has issues, one of them is retaining players for any length of time, another is developing much of anything beyond the top 2 picks in any draft, if they trade Eichel they'll be lucky to get something to the effect of a Turris and Reinhart out of it long term.
Just because teams trade players who ask out does not mean it's actually the best move for their franchise.