So long as it's an opt-in feature I'd be fine with it. My least favorite feature of any MMO is being forced to sync down in level in areas because the developers are convinced I need a challenge and there's also a few tricks I've learned in FF14 to speed level people that simply wouldn't work if this was a forced feature. It'd hurt more than harm in my case when trying to help out someone who needs to be leveled, which there still are a few on Balmung.