I solo with Trusts every day since they were introduced, I have used them for pretty much all content because my friends don't play FFXI much anymore.
I already know that the core game and Trusts etc. won't get any massive overhauls at this point, but more importantly I don't especially want the Trust system to be changed, because I view Trusts as a "strategy mini-game" and I view Trusts as a "strategy component" which I need to utilise and tinker with as part of my own strategic play.
What I mean by this is, before I engage with a Battle, I will calculate the limitations of my Trusts, I understand that they have limitations, they are a limited component in my overall strategy.
For example, Re; Re-casting Trusts during battles, I work around this by prioritising extermination of the strongest Boss in the enemy group, then my Trusts die, and I intentionally die, and I re-raise in a safe spot and call fresh Trusts to finish off the weaker bosses.
So in that example, I am in fact calling Trusts multiple times during the same battle, by understanding and exploiting the strategy component limitations of the existing Trust system.
I use Mog Garden Cheer : Jumbotender, so my Trusts have some decent Regen and Refresh.
Selecting the correct Trusts from the long list of Trusts is very important, and this is a trial-and-error learning process as part of the strategic approach to Trust gaming. The enemy you are fighting may be a lot easier if you choose the right Trusts.
And as with all Strategy Gaming, the only way to master the Trust strategic gaming, is to play it a lot, and experiment a lot. Many of today's fails will fortify your strategy to create tomorrow's success.