I do not agree that Griselbrand is way easier to cheat into play than Bargain. Bargain care not about Priest, Karakas, Cage, Metamorph & STP so these are the key differences with Griseldaddy. It is also much more flexible as you dont rely on having 8+ life to go off vs aggro meta and it is more castable.
Obviously Show & Tell gains a lot of value from Bargain's unrestriction and I think people will first try to jam it in an Oath Shell along with castable Academy Rector, Flash and maybe a 1off Emrakul glued together by 4 Cabal therapy.
That brew might end up being clunky but I think it is less of a glass canon than trying to push Bargain via a Ritual shell. Im pretty sure Ritual-Bargain (combined with Duress effects) is the reason why Misstep was left untouched for now.
Shop could jam in some Pithing needle MD to replace Thorn (fetch denial, VKey, Bargain, Bazaar) though the new Spyglass is an absolute hot contender as, again, it plays around Misstep while earning invaluable info for Prison/Aggro tempo decks!
PO in the end seems to be the real winner though I like the tension between possibly having 2 combo decks relying on 2 different engines: Rituals or Artifacts. They'll have to account for each other so, in the end, it might not be as straight forward but, PO supports FOW & Hurkyl's better so... yeah overall I think PO clearly wins.