Its slightly different, conjurer uses wand to boost its magic powr, but power is withing you. you level conjures byt using it, and by using wand s for examopkle your cure II heals 400 HPs, but when you want to cast it while holding sword, yuo alre less effective. Also you forget about other FF canon class, Red Mage, who casts spells, wjhile wearing armor and cutting stuff into a small pieces with its sword ^^ ( yes RDM is my all time fav class in Final fantasy:P).

Also yuo can be specialised. Noone forces you from puting most of your sp in dex/vit, get most of tanking skills and become dedicated tank, or hell with VIT, str/dex and youre dediated damage dealer, just fit all ovvensive skills you can find. people become jack's of all trades, when they solo, when they know noone wil be there to heal, buff, and support them, the trade edge for survivalability. And every hour they gater for extra SP ( behest) and you have a full party of Jacks ^^. I do believe that introducing more content, stuff like hard dungeones, more andanced storyline, based on party content, will turn the tendence, as [eop[e wil specialise within LS, and party to make those easier. It is not that class system is broken, its generaly game that is incomplete, and canot utilise it. its like geting TV, but no electricity.