Color dictated some slots (Vraska, for example, was the only black-green planeswalker in the set and thus had to be hybrid) as did slot placement (ten cards had to be monocolor uncommons), but mostly it was based on what rarity the best design for each planeswalker felt most suited
Again, I did as much playtesting as I could with various members of R&D, constantly iterating on individual card designs
Glistener Elf Glistener Elf may just be a 1/1 creature with infect, but it can get threatening quickly when operating an elf ball deck
Reward: Hourglasses x12, Wonder Hourglasses x36, Shop Tickets x10 Mega Venusaur's Evolution How to beat: Collect Bulbasaur, Ivysaur, Venusaur, Mega Venusaur ex (One Star) and Mega Venusaur ex (Two Star)
Tear Asunder An instant addition alongside Golgari commanders, Tear Asunder boasts that lovely flexibility kicker cards are known for
Those plot counters have nothing to do with the plot keyword