Ridiculous that it’s even a discussion; Hart is the only reason the club hasn’t been on the receiving end of the worst beatings of any British clubs in Europe - his Bayern, Dortmund and Barcelona performances confirm that.
He was a key part in elevating the club from a rich one to a successful one, and didn’t play behind a £300m defence either. Ederson has made more technical goalkeeping errors in his time here already than Hart did in 6 years - they simply haven’t been punished.
If the question is who fits the requirements of a goalkeeper in a Guardiola side more, then it’s obviously Ederson, but put him behind Demichelis and Mangala in a Pellegrini team and it’d become glaringly obvious who’s the better actual goalkeeper.
It’s the same as trying to compare Mancini and Pep - it’s moronic. Mancini turned Kompany and Zabaleta from substitutes into world class defenders, while Guardiola buys his for circa £50m each. Mancini had Milner and Adam Johnson to throw on to change a game, while Pep has Bernardo, Mahrez or Sane. Mancini had to create an elite club, Guardiola inherited one.