True, in many stories dates may not matter, but some times having a basis in time puts a story into perspective. George Orwell’s “1984” gave a year to give readers a perspective it was in the near future. Many sci-fi fiction do the same to give the reader a perspective of when technology and events will evolve. The movie the “4th of July” uses a date to highlight the significant of the plot and story.
I don’t think trying to put a timeline to Warcraft events is a bad thing.