I honestly see no point in having to level trusts. They could have easily just made it so that they synch to each dungeon and with that you could still level your own characters but dont have to care about their levels, because either they are behind (which was especially the case before they increased the exp the gained) which just makes it an annoyance or they are miles ahead of you which means that they had no need for a level system at all.

Also this system hinders people from using whoever they want. If you have leveled up Alphinaud as a healer but want to use Urianger later then bad luck..level him up first please...