But I enjoyed all fifteen books of the Wheel of Time and it had a satisfactory ending - what for me makes an epic fantasy is that it tells the story of a world-

But I enjoyed all fifteen books of the Wheel of Time and it had a satisfactory ending - what for me makes an epic fantasy is that it tells the story of a world-changing event, and world changing events have a very broad scope that involve numerous characters who could be protagonists in their own right. And that's probably going to involve more books than a series focussed on a single character or a small group, no matter how earth-shaking the outcome of that story is.