Dazed and Confused
Ludicrous speed, GO!
I see this as part of getting us ready for the playoffs, IMO Ekholm is probably one of it not the best mentors for young D. Just playing with him, getting some advice and tweaking his game a bit will go a long way in ensuring Emberson is playoff ready.
Also just added bits of familiarity is good to have in case of injuries, the playoffs aren't the best place to correct malfunctions so if we can iron out things before hand all the better.
Nothing about these changes scream to me Mike Matheson is the answer, I'm not entirely against him, but he isn't at the top of my wanted list.
That my view.
Honestly I like the direction of the defensive changes, namely Ekholm with Emberson. If you're going to increase Emberson's minutes and give him a trial run in the top 4, then learning the ropes is far easier paired with Ekholm vs. Nurse.
Nurse-Bouchard is also interesting if it can work, but I do prefer Nurse with Kulak and would rather get another smooth skating D would can play solid defence to go with Bouchard.
Honestly a prime-Sekera would be the piece that best rounds out the defence.
Sekera-Bouchard
Nurse-Kulak
Ekholm-Emberson
Who's the top pairing and who's the 3rd? Who knows. All I see is 3 pairings I would have zero issue tossing over the boards in any situation and playing 20+min a night.