To the end of increasing class diversity in raids:
I think class stacking is the true problem. There are two ways to get rid of stacking as I can see it.
1. Make the best buffs/debuffs classless (like warhorn, destro ult, etc) so all classes have equal access to them. I see two problems with this. First, it moves away from class identify and they would have to do a complete 180 on the story they are telling if they take away major vuln from necros. Second, the only thing to distinguish the classes at that point is their dps ceiling. So what are you left with? Stacking the highest parsing stam class, who will slot the best classless ultimates. It ends up not increasing diversity at all.
2. Put limitations on group based class ultimates, such that only so many can be used throughout a fight. A cooldown so to speak. Any mob hit with major vuln cannot receive it again for x seconds. This way, you could min max 2 necros, but more than that wouldn’t be necessary. You would look at other classes for what they bring.
After solving stacking of the existing class ult (colossus), you could theory craft a STRONG and IMPACTFUL group based class ultimate for every class. Every time I use colossus on a necro, I feel the awesome, impactful, and game changing nature of it. I wish all classes felt that way. Colossus is the perfect template. Both stam and mag versions give the major benefit of the skill (equal access). It would be ok to bring that magblade along, who does less dps than a stamsorc, just for that sweet group benefitting ultimate they have! People’s contribution to the fight isn’t just about their end dps number, but about how they used their group based ultimate.
The end result would be 1-2 of each class in a raid, impactful and tactical use of group-enhancing ultimates, and a reason to bring lower tier dps classes.
Two examples of such ultimates (note not all would need to be offensive oriented)
Sorc – Group Haste. Reduced global cooldown by 35% for x seconds.
Nightblades – Finish Him – Increases execution modifiers raid wide by x % for x seconds
Probably pretty damn hard to do, but boy would it make the classes pop out and feel as unique and powerful as stamcro.