I do think that the next step from ANet is to make the boss' difficulty scale with the amount of players. So it may be that we have near invincible bosses in the near future if the same amount of people keep farming them daily.
I really wish I could "Like This" more than once. If these events are going to be so popular they have to be re-made more epic feeling. Long fights with multiple stages where it's not possible to just straight out dps the boss. Make the environmental weapons and defenses more of a required part of the fight, so if some people do not defend them the event fails. Like in the initial example video of the Tequatl fight where that is the design intent.
In fact I think that's the source of the problem I have with these events, they have no designed failure-state. It is completely possible for one player to pew pew on these bosses and slowly "win" even if it takes them hours. That's not epic in my book.