Yeah god forbid your players want to play for a somewhat competitive team. They should embrace getting dunked on most nights so a couple prospects can get a little better by getting hemmed in their zone.
Also, unless you think getting help on D or offense would somehow hurt the youngsters' development, these things are not mutually exclusive.
My argument is that you don't owe anything to the players. They get paid millions to play hockey. Deal have to be made in the context that they help the team progress, and keeping your players "happy" isn't the top of the list of drivers to make a deal. Certain deal may have this side benefit, yeah for sure, but a GMs shouldn't be driven by that.
I think that KH is taking that approach too... looking down the road, he saw no short or medium term help on the wing and acquired Laine. While this is a great boost that I'm sure pleased the young vets, it's a hockey move before anything else.
Am I against KH doing deal right now? no, I think that there are opportunities for him to improve the team, but these deal have to be in step with the rebuild and make sense not only for the short term, but long term success of the team.