Some of the best games of Pokmon Ive played (not just in Expanded, but in general) were Shadow Rider Calyrex VMAX vs Regidrago VSTAR in the Silver Tempest Expanded format
However, like the tabletop version, Arena itself can have a steep learning curve if not approached carefully
Upon returning after a short lived break from the game, I was surprised to discover that in the Lorwyn Alara Standard tribes like Kithkin and Faeries made a huge impact on the metagame
Then once you start casting creatures, you get to pay one extra green mana to draw a card
Personally, while I wish this wasnt something that affects serialized cards, that aspect is a) unavoidable, and b) part of the high risk of playing Flip It
There's a memory component here, but it's no harder to track than, say, the Day/Night cycle while there are no Daybound or Nightbound creatures in play