The flaw, for me, of "High" fantasy is that one character (a wizard of some kind) can wipe out the massing horde in one "epic" battle...after readers have waited through several books or have been watchers of several seasons before deciding to do what could have been done at the end of book one.
I suppose delayed gratification is powerful for some, but apparently not for me, especially when the wizard fells the horde with a "mighty" swing of the wand or staff. Why wait?