I don't like the slowness of the leveling, but what you're saying simply isn't true. In fact, most every class has everything unlocked before level 80 except 2 talents. Level 78-80 is typically just 'mastery' gained as a stat. Most every class has all their core abilities before level 50, please find the spec and name the ability you think is >50 besides a few talent selections. Also, 40% of your abilities/passives are from your artifact, really? Name one spec that gets more than a single on-use ability from their artifact. Most of the traits don't change anything about how you play they only increase damage dealt, reduce damage taken, or increase healing done and often in some niche manner.
What you see as a way to entice people not to buy boosts, others see as a carrot to get people to even bother with leveling allied races. Why nerf exp potions? Were they afraid a new person would accidentally use them? Why nerf the heirlooms instead of just applying an item adjustment to them in dungeons (this is something that they do on the beta/ptr all the time for other gear when testing). These nerfs only hurt the people who don't want to revisit the same old content over and over and now even slower! They even nerfed the boost work-around of buying a recruit a friend account to multibox level. Recruit a friend was a choice. If your friend wanted to level slow with them, then don't recruit them or they could have added a way to toggle it off pretty easily. Instead they're forcing the choice of slow leveling or buying a boost on those who have already, often repeatedly, experienced the old zones.