The new designs take advantage of what multiplayer formats can do that duel formats cant, and subtly play up whats fun about those games
I think it's worth keeping a slot open for Panharmonicon but if you're looking to go deep into the Blink theme, I think you're better off ditching defenders and just go with Roon of the Hidden Realm or Brago, King Eternal
You can fetch out the perfect Rebel for the given situation - such as the flying, protection from Black Nightwind Glider
Sheoldred, the Apocalypse In the same vein as Standard, it makes sense to see Sheoldred, the Apocalypse take a hit in Pioneer and Explorer
The Foundations expansion is essentially designed to help you build a bigger Foundation with the Magic trading card game, as the name implies
yet) and the timey-wimey shenanigans of New Who (and similarly, other Planeswalker decks)