MTG Salvation

I agree with AvalonAurora: They should do both.

Real-world basis has been deep rooted in MtG since it's creation, such as with Arabian Knights & Portal: 3 Kingdoms. Not to mention the fact that much of high fantasy lore is based off of mythologies from various ancient cultures, such as Minotaurs & Medusas from Ancient Greek Mythology.

There is a lot of lore hidden within real-world folklore, & many of which are not common knowledge such as "Leanan Sídhe" in Celtic folklore or "Baba Yaga" in Russian folklore.

I think the main reason why WotC have been focusing on real-world settings is because of player-demand for them. There was a big push for an Egyptian-like world, hence why Amonkhet was created.

Ixalan is going to be the last 2-set block. After "Eggs" (the small set for Ixalan) is released, they're going to a "3 & 1" block rotation for the year.
The sets are going to go as followed: ("Eggs," "Soup," 2018 Core, "Spaghetti," - 2018) ("Meatballs," "Milk," 2019 Core, & "Archery" - 2019)

Once Ixalan is released, Battle for Zendikar, Oath of the Gatewatch, Shadows over Innistrad, & Eldritch Moon are going to rotate out of Standard.
Once "Spaghetti" is released, Kaladesh, Aether Revolt, Amonkhet, & Hour of Devastation will rotate out.
Once "Archery" is released, Ixalan, "Eggs," "Soup," & 2018 Core will rotate out.
& so on & so forth according to MaRo.