One of the problems mentioned by Blizzard was that when there were 120 levels, each level just flew by so quickly, there wasn't really any chance of trying out your abilities at a reasonable pace. The pacing was completely off. You have 120 levels, but each of them just meant so little, as levels would just be raining down from the sky. No chance for gaining a level to actually feel meaningful. And that was already the case with just the heirloom experience bonuses, before the Winds of Wisdom buff.
Check back here with what they said regarding this
https://youtu.be/6OHDAwg-Tw4?t=899
Now they've reduced levels by more than half. Perfect time to tune the pacing of leveling. But what does the pacing look like? Levels still fly by really fast. We now have way fewer levels, and gaining a level is still trivial because you spend mere minutes on each level. Had they actually wanted to make gaining levels more meaningful, they should've increased the time it takes to gain each individual level.
It's just not possible to deny, with a leveling time of around 10 hours, even if you're taking your time, it's just way too fast. It might not be too fast for you if you hate leveling and just want to be done with it. But as far as making leveling an actually compelling experience, making the act of creating a character and taking him on a journey actually exciting, especially in regards to the new player experiencing this for the first time, it's not achieving what they claimed they wanted to do.