At the moment, the quests are done before timer starts, then turned in in burst as event rolls over. And, yes, much like siege sign up, it fills in just a few seconds, leaving the remainder of the event to do quests for next round.
Tweaking the numbers could work, but I am thinking if I would be happier with a more traditional event structure. In other events, you can't preload. The work on accomplishing the events starts when the event starts. Here, 99% of the work - the killing, the gathering, the deliveries and escorts all happen beforehand, making the event be a mad scramble to complete that last 1% by turning it in.
While we are at it... I am not thrilled with John Selino not letting you buy stuff if you are not top finisher. I presume this was done to combat botting, but it makes it rather hard to redeem justice points.
-- Rustyx --- 92R / 92S / 92M on Reni (Guild KnightShift). Yes, running the new FOTM R/M, cause I am not elf enough to be WD/S.
Oh, and people who have more than 3 classes are clinically insane.