This was a good thing?What game are you playing? I can tell you one "unique button" without even thinking.
Feint.
Top guilds in my realm were hunting for Rogues like the plague just because of their soaking capabilities. Even subgeared, or unexperienced people were being looked over veterans just based on class.
The same also happened to a large extend in EN with different classes. I didn't play NH so I couldn't know.
The homogenization helped nothing at making some classes distinctly superior than others, yet it killed a lot of the fun of messing around with group composition.
Now raids are mostly "Stack whatever is good at the current patch".