We would actually rather see a group get by on a combination of diversity, utility, and skill in Tera. We do not really like the idea of needing the 'holy trinity', not that we see anything wrong with it. We really do not like it makes a lot of skills to be successful based on the idea because it would undermine the curve for the casual player. However, we believe that a truly skilled team will tear through the content faster, which is well deserved.
We personally would like to see teams succeed based on twitch-thinking and reactive tactics. Each class(tera gold) should have a practical tool, in different ways under different conditions of work. The idea of a group sitting in front of a boss and saying "Okay, so as usual we're gonna do blah, blah, so-and-so will blah". Tackling every encounter the same way is boring. We should be forced to use tactics and switch twitch fly. We believe that communication and understanding of your teammates are in the online-oriented game, the most important skills.
This would however need to be considered in both class design and enemy tells and AI. Raid bosses in particular we believe should be more like console game bosses. Where you need to kind of 'solve a puzzle' or use the environment to make it vulnerable for a few moments while you pound it to death, it gets up, and the lower it's health gets the more difficult it is to bring it to that point of vulnerability.
Capricorn