This is sort of what I was trying to get at. There should be some content that caters to the people who want an event like dynamis, but dynamis worked best with a tight knit group of people who showed every run, followed instructions, and took the time to learn what they were doing. When dynamis needed 30+ people to do successfully it was very hard to find that many people willing to commit four hours to an event. The people who weren't committed or couldn't follow instructions linked east gate every run.
Tanking for four hours was a lot of work too. At least in XIV you could rotate people's jobs around and that might make the event more bearable to people with critical roles.
Most players are probably going to want shorter events, but that doesn't mean SE should make everything cater to the average player.