I guess you're having trouble understanding my suggestion.
Right now, this second, you get 5 days for this event, and then "its done." If you don't get your gear in those 5 days, you are SOL.
My idea changes nothing. You still get the exact same 5 days. Its just any 5 days once the event launches. It could be the first 5 days after launch. Or it could be 2 years later, for 5 days. Everyone gets the same 5 days, its just that the 5 days aren't restricted by the calendar.
Then, in addition to those 5 days, Turbine can provide ways to get more days. One idea is DDO Store, buying a "24 hr pass" for X points. Another is to "re-gift" X days to everyone's account to "re-celebrate" the Event.
So, the new event would launch and everyone would get 5 days to play it, to be used whenever they want. If a year goes by, Turbine can re-gift another 5 days to each account, and/or sell time in the DDO store.
So, tell me how this idea, IN ANY WAY, makes it any harder to get what you (YOU) want from the events of this kind?