Debates go on all the time about the DO and TG. Lots of people try to figure out who killed Asmodean, what exactly is meant by "Rand's blood on the rocks of SG," or how Alivia will "help Rand die." These are big questions that (excluding the first) the author(s) wanted us to read at the "appropriate" time.

Even in a series that doesn't have the WoT's grand scope, there are always going to be minor questions that are left dangling. "Minor/petty questions," to my mind, would not be about things that are important or necessary to finishing the Light vs Shadow conflict, nor to resolving the futures of our major players. A good example would be "Where are the Ogier actually from?" or "How and why did the Ogier get to Randland?" You might wonder about it, but the story can be resolved without ever addressing it.

Another popular one could be "How did Narg learn to speak human language?"

So if you could get answers to 5 purely petty/minor questions, what would you ask about?

My own (not completely off the top of my head):

"Why does the Tree of Life not grow any off-spring, and how did the Aiel get the sapling that was sent to Cairhien?"

"Why exactly do the WO think that entering TaR in the flesh is evil and causes loss-of-soul (an official symptom of Claritin-D)?"

"Who made the Portal Stones, were they invented for more than mere transportation (e.g., research), and how were they made?"

"Does Fortuana really think that "choosing not to channel" makes her different from other potential channelers?" and

"Since Elyas is an experienced Borderlander and Wolfbrother who knows that the Last Battle is coming, why isn't he doing anything about gathering the wolves for TG?"