I'm going to get this out of the way right off the bat since I know I'll get a dozen people asking again this week: Yes, Know Your Lore will be coming back, it is not gone forever. I promise. I will pinkie swear on it, even. Come on, who wants to pinkie swear? Anybody? Anybody?
"On the topic of the Nerubians and the Qiraji, is there any relation in the lore between the two? Or are two insect civilizations coincidental?"
There's absolutely a relation between the two. They hold a common ancestry. Both the Qiraji and the Nerubians are offshoots of an even more ancient race, the Aqir. Way back when Azeroth was still very primal, and Trolls were the top dogs. There were three major players in the world: The Amani Trolls, the Gurubashi Trolls, and the Aqir. They warred for thousands of years. Thousands. It was a war of attrition on the grandest scale possible, and all involved more or less broke under the weight of their losses.