Hate it. Even the whole level sync makes me writhe in agony.
The idea that low level content almost always takes x2 or x3 longer when geared than its lvl50 counterpart to me is just silly.
I find that one of the most rewarding and satisfying reasons to play mmorpgs is to get stronger and develop your character.
Level/item sync is just a massive wall to this. I understand its purpose, but to me it's just not warranted enough.
Imagine how great it would be to take one of your mates through some old content who really needs it for the clear or the gear, and being able to just go in together and smash it, without being burdened by queue times or required roles.
If you can only use the full capability of your ilvl 110+ gear in a small percentage of the game content, then it really minimizes its overall value.