Sorry if this has been covered a bunch, but is there's a persona in this one similar to Yoshitsune or Trumpeter in P4G, that I should be aiming at?
I've been getting new ones from fights and fusions, but I still feel like all of my persona are terrible.
I'm just done with the third palace, and am level 26.
What exactly do you mean by "terrible"? Of course there are endgame personas which have a lot of cool and strong skills, but you are still very early on, so you having "bad" personas in comparison to those is only logical. And what do you mean by aiming for them? As a rule of thumb you should just constantly fuse personas to stay ahead of the curve a little and to flesh out your compendium, for the late game fusions you will need a meaty compendium.