I dont raid or do Savage/EX's and yet I'm not fond of the idea of having trusts for Savages, Extremes, Unreal, Chaotic, etc contents. I feel it would not be a cost effective use of Square's resources. That said, I do HIGHLY encourage them to add trusts to ALL MSQ Trials/missions, etc with the sole exception being the Crystal Tower series Aliiance raids.

I advocate for trials/missions having trusts because as someone who regularly replays the MSQ using Trusts for story reasons it is frustrating beyond belief to get stuck at the older trials/missions for 30+minutes while waiting for folks to queue. It kills the flow and immersion and its nearly always during a peak moment when your excitement and eagerness to continue on is the highest.
Please SE, for the love of all that is holy. Before you add trusts to another optional dungeon, give MSQ trials some trust love first!