Changing Class in Dungeons

[Gnova]

Personally I think this is an entirely acceptable way of playing the game. In fact, it will fully utilize the Armory system.
- The "Need" function can be locked to the job you first enter with.

You can't balance content with that playstyle.
Either you assume everyone had multiple jobs leveled and then make it impossible for groups filled with single job players or you make it ridiculously easy for groups that do job switches.