Have you ever considered an optional level sync for dungeons and wilderness areas and mandatory level sync for pvp arenas. You could probably create a data table to keep data such as skill, enhancement, and equipment bonus limits and remove any abilities that require a hire level and drop hp equal to the number of levels different. This may still leave higher level players with an advantage but it will allow higher level players do more with lower level players without creating a new character. This allows higher level players to act a mercenaries and guild members help new recruits. This will help promote a community togetherness that could enhance gameplay. This is just an on the fly description, I'm sure you have the resources to take it further.