I personally loved the partys in XI, I rather hate the way most new "Mainstream" mmos are doing it. But that is my opinion there is obviously an opposing one.

Solution: variety of way s to level. Some Mindless grinds as some put it, some group based raids, some group based defense, some solo activities, some quest level. Add in alot of way to level = win, force 1 way, no matter what want that is = complete fail.