While I like such idea in priciple with any feature like that there will be space for missuse - players pairing on purpose with lowlevel characters to be able to spiritbond or train their chocobos or fullfill various challenge log entries easier / faster etc. If you really want to help / play with newbie friends why not use another class or even make an alt? I know you'd loose some benefits in case of alts (like mounts and gear and so on) but might be still better option than tagging around "bored" in your shiny 100+ iLVL gear instakiling any mob you might trip over ...