I'd agree to Ilvl syncing the last bosses of expansions, but that's only to give them an additional layer of epicness, immersion, and difficulty that the last bosses should be worthy of. However, anything else should not have an Ilvl sync because that would completely kill the sense of getting better gear in order to become stronger. What would be the point of getting 10+ ilvl gear if the boss or the dungeon would remain the exact same to me? I need to feel the difference, to know that I got better, stronger, and faster. The game should reward you for getting better, not just "Get ilvl to access X instance".