Over the years, I have occasionally dunked on Guild Wars 2 for making its story content early on revolve around taking part in continually rolling limited-time events. That was a bad idea. But it was also a fairly new idea, and while I may maintain that it should have been recognized as a bad idea earlier than it was, I can’t fault the developers for trying something novel. That’s a good thing. You can’t really fault people for trying new things and new ways of incentivizing logging in to play new content.
That having been said, I do think story content being a limited-time event is a bad idea. But what is a good idea? Lots of games have limited-time content ranging from yearly or monthly festivals to special PvP series or the like. But what do you like to see? What sort of time-limited content works well in MMOs, and what doesn’t? It’s hard to argue that you should be able to access a Christmas event year-round without a profound sense of solipsism, but what do you think does and doesn’t work?