While I like the idea of the set bonuses, I hate what heirlooms have done to the leveling experience with a passion. Let me start by saying I have a couple dozen max level characters and full sets of every type of heirloom.
That said, a large part of what makes leveling those characters feel less fun then it used to is the fact that so much gear is insta-shredded because of my heirlooms. I wish the heirlooms were turned into enchants that gave maybe some bonus stats and these new fun set bonus effects. Having your character not really grow in any significant way after completing a dungeon or tons of quests feels counter intuitive in an MMO. I miss finishing a dungeon and equipping a new green I lucked out at or possibly a blue that I lucked out to find or was shared to me by someone who got a lucky drop.
I miss targeting specific dungeons through out the leveling process because I wanted my druids of the fang gear or what have you.
I’m sure there are many others with differing opinions, but at this point, what is the point of leveling to 50 if you don’t even swap out much of your gear as you get stronger…