This game will always have a combo of dark and light-hearted. And it will always remain PG13.
Time people got over it. And no, nothing started or ended with the introduction of Pandaren, plenty of dark stories in Pandaria. Tauren and Draenei were in the game long before that, as were Gnomes, and Dwarves... And the Vulpera are fierce little scrappers.
I'm well aware that people have selective memories and sometimes even outlooks on present facts, but jeez...