If Schneider is good enough to cause a roster issue on a RD that features three or four of Trouba, ADA, Fox and Lundkvist, that is a very good thing for the Rangers. Because that means either Schneider is doing damn well and making that an issue, or someone is having a really difficult season and might not be the long-term lock we'd hoped they'd be.
Either way, that's value for the Rangers.
When it comes to young, talented, right defensemen on reasonable contracts, I don't think we're looking at diminishing returns. I think diminishing returns is when you have too many goalies, or a tweener who might be over-acheving and coming up on a new contract.
But if the Rangers get to a point where they have to move one or two of ADA, Trouba, Lundkvist, Fox or Schneider because they're all NHL-calibre players, they will get have a nice portfolio of opportunities to use that to their advantage.
Because just like we're looking for those nice ELC or second contract players via trade to fill holes, other teams will be doing the exact same thingto fill their own holes.