The Warriors second job isnt really that different. The only difference is
what weapons they master, and a couple abilities.

Fighter:  Axe/Sword user
  Can boost weapon attack of party
  Can “return” damage from enemy

Page:     Sword/Blunt weapon user
  Can lower enemy wep def
  Also returns damage from enemies

Spearman: Spear/Polearm user (unable to use shields because of this)
  Raises party’s wep def and mag def
  Raises party’s max hp and mp by 60%
 
All these members get final attack, weapon booster, and mastery.
The reason why you choose a class is for what they become in the future…