Now this is news to me after completing Turn 5.

I do not have much to comment on Turn 5 since it closely resembles how raids are today compared to the other encounters. It's the entry into the Morbol journey, it's the entry into the UCoB journey. The fact that Twintania was used this often for content shows how timeless it is, albeit the randomness of it all. I actually would much prefer content to have more randomness rather than mechanics being a 50/50 or a 33/33/33 or even a 25/25/25/25. It feels formulaic and quite draining to do.

A lot of the higher end content tends to be just a choreographed dance or note sheet. Each class having a different dance to follow and each instrument just doing their part. With randomness added in, it would probably incentivize every person to learn how the mechanic works rather than just the tank/healer/dps learning what they do. It's a sense of awareness that you develop and it's kind of a lost art.

Well plugins kind of killed raiding.