thanks for those infos, I wasn't aware that the npc told you. I would still like to stick to this suggestion, as knowing the date + time in game is still a bit hassle to figure out in my/your timezone. It might be easy if you are just off a few hours from server time, but if its 17 or 9 or 13 hours, then I personally find it annoying to do timezone math
Also, such a countdown would put all the times in one place. As Poring Slayer said: npc, forum, wiki... thats a "lot" of places to checkc ;-)
There could also be a timer for the next hero birthday and other interesting/cool dates and woe.
Apart from helping those of us, who aren't so good with the timezone math, it might actually increase participation since more people might know about the events