Fortisphere was likely taken out of circulation because it was a one-cost card that could be used as a way for Steel decks to draw up extra cards
Once per turn you can put a card from your hand face down into the ink pool (inkwell) and by doing so you will have options to pay for higher cost cards in your deck
As such, it lends itself very well to deck upgrades, but even if you forgo upgrading it, Limit Break is still a great deck to play with out of the box without any alterations
Hence, it's more likely to stick around and keep giving you value from the Proliferate on Tidus
The five-ink amethyst card has the hilarious ability Forget the Coach, Heres a Sword - a fun play on her pumpkin-transforming powers in the movie - that can buff all of your characters strength at once
She's an interesting card that you don't want to play as soon as you add her to your hand, as her ability, Perhaps We Can Save Our Future, affects all character cards, including your own