If they do want it to be "class is better for solo and job is better for party", then they need to retool the classes even further, and not be afraid to have all the base classes step on each others toes.

The classes would have to each be able to fulfill multiples roles. Gladiator would have to lose some defensive abilities and traits and gain some offensive abilities and traits, which would be lost and replaced (the new offensive traits and abilities) upon switching to PLD for defensive/support/party support abilities.

A change like that for all the classes and jobs is how that would work. The classes as they stand now, for the MOST part, are just watered down classes. Adding class specific gear, doesn't change that.