Corrigan had a couple of very dodgy seasons in him and Hart has a few howlers in his back catalogue. Never saw Swift or Trautmann they may well have some back in the day too, so can't say but from what I have read it seems it would be one of the 2 older ones. Modern goalies need more all round skills to can see Ederson getting up there on initial impressions.Or the save against Leeds where he dived one way and completely twisted his body 180 degrees and got one hand to a header. I have seen the save back on YouTube and i have to be honest it was bugger all like I described but that's definitely the recollection I had in my head and it's still the best save I have ever seen even if it wasn't quite as good as my memory remembers it
I think all you can do is judge them against contemporaries, and if you haven't seen them play, go by reputation. Swift and Bert were each widely rated throughout English football as the best in the game in their era, and by a mile as well. Would you say that's the case with any of our later keepers? I don't really think so, though it's harder these days as the competition comes from some of the best goalkeepers from all round the world as opposed to just Britain and Ireland.
Ederson does look very good so far, though. Hope he lives up to this promise as he appears to have everything needed to be a really top 'keeper in this era.