Imaro
Legend
I think we're just seeing a broadening of what the class bucket contains. Instead of just determining what role they will be, they will now primarily dictate what their "shtick" is... Fighters specialize in using weapons effectively to do whatever they do.
A Fighter that's a striker seems to be about using weapons to do massive damage, as opposed to a rogue striker that seems more about using stealth and trickery to deal that damage.
I'm also guessing all the "new" roles we see in classes will cover areas they "kind of" dipped into already...
I'm gonna deny that it's just a broadening of the "class bucket". I think originally class and role were pretty much tied together to the point where a class, for the most part, defined what role you were playing... now having a fighter in the party doesn't necessarily mean you have a defender. Again, I see this transition as pretty much making your class obsolete.
I also wonder how this doesn't blur the lines as far as classes such as the Slayer vs. the Barbarian or Archer Slayer vs. Archery Ranger... on the other hand why isn't an Avenger just a lightly armotred Paladin build?