Has a massive amount of skills that all level through use and increase the related skills strength, you also have a traditional xp and levelling system that provides skill points to spend on abilities

Has both an activity based system, and traditional level system, levelling skills through use provides xp to your overall level, and levelling that gives a skill point to spend on the skills.

Abilities and skills are learnt from trainers across the map, from that point doing anything related to that skill will increase it's xp and eventually level it up.