J-H
Hero
In 5e, it should be stable and viable. All classes are viable, and most classes can fill most roles.
Wizards can tank.
Fighters can do respectable to excellent ranged damage (a bit weak on AOE).
Rogues can survive relatively well, and a team of all rogues will be all sneak attack all the time.
Bards and Warlocks can do some of anything.
Druids can do just about any role.
Rangers have some nice gish-yness and should be able to do a good job bypassing encounters or engaging on favorable terms.
etc.
I think Cleric would be the most same-y since Clerics have relatively bland domain features and all end up picking from the same spell list.
Wizards can tank.
Fighters can do respectable to excellent ranged damage (a bit weak on AOE).
Rogues can survive relatively well, and a team of all rogues will be all sneak attack all the time.
Bards and Warlocks can do some of anything.
Druids can do just about any role.
Rangers have some nice gish-yness and should be able to do a good job bypassing encounters or engaging on favorable terms.
etc.
I think Cleric would be the most same-y since Clerics have relatively bland domain features and all end up picking from the same spell list.