The solo instanced battles.
Been trying to beat Sinking Dosmaga for over a month. Of course without it I cannot get smn or sch and my character is really not up to doing the main story quests. There is no information online and of course I cannot just overpower it with a high level character. Same problem with my other characters. I reach a point I cannot go farther, even they are 50 legacy characters. Have a 50 conj but cannot use all my spells so I am not a good healer. Much prefer FFXI rank system. You kind of need to do it but you get to have a party with you and there is information available on how to do them.