I could just say that Chevy "is content with the current top 4, and he addressed the LHD depth by acquiring Strait". But I don't think you would understand that, so let's go a bit more in-depth.
If we do this trade, we no longer have a top 4 LHD. What that does is a) forces Trouba to play as a LHD, which might become problematic if he specifically wants to play on his natural side, b) forces us to use Myers way too much from the start of the season, which will again be problematic with his surgery concerns, and c) forces Morrissey to play in the top 4 with NO ONE to shelter him with, aside from Trouba.
We'd look like this.
Trouba-Buff
Morrissey-Myers
Emelin-Chiarot
We don't know which Myers we're getting - the one we know from the year's worth of games he's played with us, or the one who struggles with the same workload he has had before surgeries. And he won't have Enstrom to help him out - instead, we have a rookie with a whopping one game of NHL experience. He has to fill the shoes of a 21 minutes a night, top 4 defenseman. A fantastic idea, isn't it? At that point, having Emelin around is kind of redundant. He is a good #5D to have, although overpaid, but having a #5 means very little if your top 4 is not looking healthy.
Do you honestly think that after the expansion, with Enstrom and without Dano or whoever gets picked, we would be better off than with that defense, Dano and no "Armia"?
We will not be losing anyone who we couldn't comfortably replace in-house in either scenario. So, tell me: why the hell should we downgrade our defense and create a massive liability?