This would still be abiding by the "holy trinity", you'd just have more options as far as picking your tank/healer/DPS goes. I think the problem you're having right now is that you still see LOTRO in the pre-HD class system where class equals role. That system hasn't existed in game for years.
When people say that every traitline should be viable/competitive what they mean is that every traitline should be able to stand on its own. This isn't a request for homogenization of classes but rather a request to diversify. LOTRO needs to work on splitting up the traitlines to the point where each class is 3 different classes in practice, this current situation where DPS lines like red RK retains two rezzes from the heal aspect is honestly awful to balance.