It improves the PK, gives the team the best 3rd line in the league, and at this point, Green's likely not getting more than 17-18 minutes per game. Before Niskanen? Yeah it'd be a tough trade to swallow. After? It's one of those 'build a team' trades, rather than a 'win the trade' trade.
And Johansson is not better than Helm.
I don't agree with anything you wrote. It's a terrible idea on every level to trade 2 better players for 2 worse ones. Yes, Johansson is better than Helm. He's more versatile, is younger, and has a higher ceiling. And even if I grant you that Helm is slightly better than Johansson, Green >>>> Kindl.
A "build a team trade" does not entail sending out better players than the ones you receive. Kindl/Orlov is a garbage 3rd pairing. Kindl/Orpik is worse. Trading MJ90 for Helm does nothing to address our 2nd line, and in fact gives us little to no insurance to injuries in the top 6.
It's one of those "terrible use of assets trade" which would be right up our alley. If it was Green for Kindl + Helm, I'd consider it. Adding MJ90 is a joke.