Why are we spending so much time talking about the D personnel? We have like 8-9 NHL caliber forwards on the current roster. And literally no NHL ready prospects who will be able to step in for a while. Depending on what we do with Fast, Kreider and Strome, we may have even less.
As for moving any of the D for help upfront, it makes no sense to move anyone that is young and proven -- unless we prefer a 5-7 year rebuild.
If we start trading away the D that are reaching their potential now, we'll have to wait 3-5 years before the next batch reaches theirs.
Beyond that, we should avoid trading young NHL d-men until the whole team is playing a more sound defensive structure. The three biggest culprits as far as making our D consistently look bad:
1 - not having 5 guys in the picture (aka the forwards are not consistently defending/supporting the puck well enough)
2 - goaltenders who handle the puck and rebounds like a hot potato. (anyone not named Igor)
3 - not consistently slowing down the opposition in the neutral zone.
When these issues are addressed more consistently by the goaltending and forwards, our overall defending will look a lot better. At that point, we'll be able to better assess what we have with our current D personnel. But also, it'll be a lot easier to develop these kids at the NHL level.