The meta for squadron tactics is almost brain-dead but it's still more than what you can do with Trusts. Trusts are really a worse version of squadrons for players who aren't too lazy to push 2 extra buttons once in a long while. They rarely use AoEs, they stop doing everything they're doing to evade mechanics, they're slower than snails, and you can't even adjust their offense x defense stat priorities.
Leveling squadrons up has the added benefit of making missions easier to complete, increasing the range of guaranteed rewards you can get. The only reason you level trusts is to change their costumes, which look pretty meh anyway.

Giving Trusts a little teensy extra depth and flexibility wouldn't affect people who are satisfied with their current shoddy implementation but it would satisfy people like me more as well. As someone who completed every squadron related achievement I never had any issues leading them through dungeons, even with the dungeons not being designed for squadrons, so their explanation that dungeons needed to be designed the way they are because of Trusts/Duty Support has always sounded like complete bullshit to me.

Trusts right now are nothing but glorified training wheels for insecure players at best, or a tool for the typical Limsa AFKer subscriber to also AFK-level at worst.