Shouldn't affect Leyline's functionality at all.
There is some question as to whether or not Wishes and Research will be able to get cards in the Exile zone. As currently worded, Exiled cards would not be retrievable by such cards, though it is possible that the Wishes and Research could be errataed to include Exile as a legal zone for them to retrieve cards from.
They pretty clearly said that that would not be the case:
However, the acknowledgment that this zone is, in fact, fully within the game does bring about functional changes to the six Wishes, Ring of Ma'rûf, and the Research half of Research // Development. These cards let you get cards from "outside the game," which has been ruled to include your card collection (in casual games), your sideboard (in tournament games), and the removed-from-the-game zone. That's no longer the case. Exiled cards are not outside the game (and you could argue that they never really were), so these cards will no longer be able to access cards in that zone.[/quote