What happens when your game evens out and low level zones are empty?
Since you pretty much pass through the first 15 levels easily with no help from others, this really shouldn't ever be an issue. If this were FFXI and it was still using traditional 6 man parties for leveling all the time, then I would be concerned. But it's a nonissue in this game (and if you can't solo lowbie fates that are appropriate for your level, you're doing something wrong- hell many low level fates practically win themselves)