I would like to suggest a "rework" to how barbarian tickets are used after unlocking all levels. My thought was to create a shop with Otto Godblessed where you could spend barbarian tickets in order to purchase various skilling related items.
3 Barbarian tickets = 2 Combat or Skilling tokens
6 Barbarian tickets = 2 Catalyst tokens
50 Barbarian tickets = Skilling Equipment box
100 Barbarian tickets = Mystic Lamp
1,000 Barbarian tickets = Unique Barbarian cosmetic armor set(Something along the lines of Thok from Runescape 3)