There absolutely is a denial, a prolonged and wholly unjustified one.
That “intricate path?” It does not add anything to the game or experience. At the very least, it does not add anything even approaching the value of the cost of removing flight for the majority if not entire time given content is relevant.
Having played those expansions? Loved those expansions? I can say with absolute, total, 100% complete “the sky is blue” confidence that no there was not.
A paltry handful had restrictions either due to being Classic zones originally developed without the concept, or short lived “patch” zones like the Molten Front. BC and Wrath and Cataclysm and Pandaria release zones were all flight based with the exception of the leveling zones where it was reasonable to expect not to fly at that point anyways.
And no, the zones that didn’t have flight weren’t better for its absence either.