Skill Trees, faction ranking bonuses, Specialisations. If you consider Runescape an MMO then all your skills are permanent progression for your character. Now when I mean "permanent progression" I don't mean it never changes or gets expanded with expansions and what not, but the majority of what you have in there will always be with your character for the remainder of the games life cycle like abilities and skills. Destiny will have none of that once sunsetting goes in since all the permanent player progression was on the gear you collect with there being very little player progression beyond that. "Power Level" I do not consider a 'real' permanent player progression system as it doesn't have a long term benefit for your character and serves as little more than a gate to content. All my guns? Sunsetted. All my armour? Sunsetted. All my seasonal mods? Sunsetted. My Artifact mods and progress? Sunsetted. Why would I invest time in an MMORG game that has no permanent progression for my character making any 'progress' I do make redundant within a year?