I think it's a bad look for an organization to move on from a guy to whom they gave a long-term contract after a single season. But as quickly as year 2, should situations have changed, I don't think any UFA would begrudge a team for moving a guy out. Players are more than happy to have simply found the contract terms that they wanted; having to honor those terms for another organization is merely part of the business.
Giving up on a guy after one lackluster year has the feeling of doing a guy wrong. What if the Blues had said, "nope - we've seen enough" after Justin Faulk's first season? He'd probably have been pissed having not had the chance to rebound after an adjustment period; and guys let other guys in the locker-room know what they think of a city/management. If he's immediately traded to Winnipeg, that doesn't go un-noticed.
Krug's had 2 full years, and is an asset for which Armstrong should have freedom to use however he sees best fit for his hockey-franchise. No different than any other player without a NMC.
Yes - this.