It has been awhile since this has been brought up, and I felt it was time to revisit it. Especially with all the changes to old raid systems which have already happened and are in the process of happening.
As most of us know, the current mechanism for the raid timer lockout is that it begins when you pick up your end reward. Forget to pick up your end reward, and chances are you won't find out until you are trying to get in again.
There is also a timer mechanism on epic quests. Unlike the raid timer, epic timers begin when you complete the quest. It has nothing to do with picking up the end reward.
So the suggestion here is to make the raid timer mechanism the same as the current system for epic quests. I am not suggesting any change in the duration of the timers, just that the timer should begin on quest completion, not upon picking up your end reward.
For those who would argue with the rebuttal, "Collect your reward when you exit, and this is a non-issue." I would reply that everyone can mess up once in awhile, and it isn't always you messing up that affects you. If your good friend forgot, and therefor couldn't join you, or a class you felt you needed, or whatever. It is an inconvenience that isn't necessary, and as we already see a system in-game that works better, perhaps it could be an easy solution to implement.