@cardraptor6: Since Theros actually has a card that cares about Walls (likely in a flavourful nod to Invisibility), I wouldn't discount it just yet.

I actually think the biggest reason they would NOT do it is because the card is refering to Medusa with its name. I don't think "Medusa" would even be a name in Theros, much less that of any gorgon. It is, after all, a FANTASY setting.