I've been leveling a Blood Elf Mage and a Nightborne Rogue for gits and shiggles at the end of Legion's lifespan, and I can say that new leveling definitely requires you to be careful about pats and actually use your toolkit - depending on class, of course. My Frost Mage spammed barrier off CD, had to use Frost Nova if she aggroed something unexpected and frequently had to eat conjured food between trash packs. Meanwhile, the old leveling with heirlooms was basically just throw two Ice Lances on non-frozen enemies and they would just die. I wouldn't say I have to understand the full Frost Mage rotation (the way they handle procs makes it kinda hard to screw up the basics) and I didn't have to use that many CDs outside of the occasional Frozen Orb, but it did require some kiting with Blink in some cases and the odd interrupt here or there. It was kinda engaging, but at the same time kind of tedious because these characters are alts and I felt like I could just read a guide at 110 if I really wanted to understand my class. I'm not sure it really added much to my leveling experience, tbh, but admittedly that's from the perspective of someone who has like 6 level-capped characters already.
It's still infinitely better than FFXIV's leveling where you're mashing the same three buttons until as far as level 50, in a lot of cases - with a glacial GCD, to boot. WoW's changes to zone scaling though, while great for alts, seriously fragment the game's already-fractured narrative and I don't think that's great design. I get that players felt like they were outleveling zones without seeing the entire zone story, but now you can just do introductory quests in basically every old-world zone and still hit 60, and there's not a lot of cohesion as to how the stories tie together. Also, given how tedious I felt leveling was WITH heirlooms, I can't imagine how it feels to a new player in plain ol' whites.