Myers is not done developing and will very likely improve substantially at his next stop. He still has done very little to merit moving Mantha for him who has limitless potential. They shouldn't move Mantha for Myers in my opinion. There are suitable trades, maybe not to the Buffalo fan-base but there are options where we don't have to send Mantha or Larkin and if they don't win that fine, but there is no reason to become fixated on him and pay too steep of a price.
However, he is by no means done developing. 25 year old D-man are absolutely still developing.
Substantially? That's
highly debatable.
Goligoski, Edler, Kindl, Enstrom, Jackman, Hammer, Liles, Gleason, Leopold, Hainsey, Meszaros, Coburn...I mean, the list is practically endless of guys who either improved marginally, made no progress, or even regressed around the age of 25 or 26 and still haven't gotten that back.
There is this amazing phenomenon where people forget that many guys who are now considered "meh" players at the age of 29 or 30 were once "the next big thing" or "untradeable" or "the only way to go from here is up" kind of players. I mean, the fact that we're even talking about trading for Myers when many Sabres fans were probably ordaining him as a franchise player 5 years ago speaks volumes.
As a Wings fan, I'd be extremely hesitant to say a defenseman is "absolutely still developing at 25." We, better than anyone, know that not all players have the same development trajectory, given how many people like to detract from our youngsters who weren't NHL regulars at 21.
With that said, I do think Myers will look better on a winning team. I think we as fans often underestimate the toll it takes on players who have to carry the lunch pail to the junkyard every day. I think players who can keep the hardhat on while playing for a tanking team are few and far between and I don't fault them for that. There's little fun in giving 100% for a lost cause. But development wise, I wouldn't bank on Myers developing "substantially" just because he's 25. Most NHL defenseman don't have 130 games under their belt before they could legally crack open a cold one stateside either.