it wasn't that revolutionary. You equip abilities in ff5 to use them in battle, you equip relics in ff6 to get abilities, you equip materia to use abilities, etc

josef dies to save you from being crushed by a rock, tellah dies for reasons I really can't remember because I don't like that game and haven't played it in a coon's age, galuf dies to save you so you can lay some smackdown on exdeath, etc

ff1 was revolutionary in that you had big nice graphics on a new system, ff4 was revolutionary in that you had big nice graphics on a new system, ff7 was revolutionary in that you had big nice graphics on a new system, etc

Pretty much the only truly revolutionary thing is how these games revolve in circles to have the same linear growth in features.