I think there could be a place for a system like this, honestly i have an issue with SE personally putting level sync restrictions on dungeons after 50 (Wanderers palace and a few others springing to mind.)
to ' save the difficulty' when it just negates improving your item level and getting stronger, if they want to save the difficulty of said dungeon make it an optional thing and don't force it upon players.
I can understand doing it to dungeons that are progressional pre-50 so it's not just stomped through by randoms in the duty finder, however anything after 50 should not have its level sync forced on anyone, if people want to experience the dungeons difficulty then give them an option to switch to it, especially dungeons like WP which you gain nothing from doing unless you're a fresh 50 looking for some item level 55 gear to help you get into HM primals and to help with crafting your relic weapon.

Instead of being something the party leader switches on though it should be an option within the Duty finder you can toggle when selecting that dungeon, i can't stress enough how having my item level synced in an end game dungeon via the roulette just makes me want to leave outright.