Maybe what happens is players use end-game fight potential as the basis for what makes one character better or worse than another. In this case Tita is low-tier because she can get one-shotted by certain S-Crafts and Crafts at that point, and her crowd-oriented attacks don't have much use on the low number of enemies you fight per battle. But for most of the game Tita can be more than useful, and not just for crowd control. I think
s by far the worst member you could bring along into the
character's so underpowered and devoid of useful Crafts that people whining about Tita must be forgetting this one because who even cares. I don't think Tita is a great optional party member compared to beasts like Kloe and Agate, but she's closer to middle-tier.
Re: EP/Arts balance, it's nice having more expensive single-target offense just in case you need to finish an enemy off quickly and know you aren't using too much EP in the process. There's usually more benefit in the long run to abusing the lowest- and highest-potential offensive Arts throughout, though. EP costs for Arts are well-balanced; you should be using the best EP Cut Quartz on casters as much as possible. What Falcom should have done is provide EP-regenerating food items, whether as sit-down meals or to-go or both. Inns are somewhat more useful than they ought to be thanks to cooking being underpowered in this one sense, but I'd rather have another reason to cook.
Also, Zane or Agate w/Gladiator Belt can be dangerously OP. Zane's still better against mobs than Agate is against bosses, though.