Espers really worth it?

[Renmiri]

A few of them are still pretty useful. Chaos, Ultima, and Zodiark are all still useful by the end.

I like Mateus with Cura and that ice lance thingie

The main problem with them, is they have no defense, so if you don't watch it, they get killed quickly before they can do anything useful.

Aye, plus having your character there makes you even weaker.

I personally like how well balanced they are compared to previous games in the series.

I don't follow....