I hear you. Goal keeper is just the one position where you would expect it will be hard to find a top class back-up.
Essentialy most teams stick with one goaly in the EPL, which for stability sake makes sense. However this means the back-up plays, if lucky, only in a few cap games and most likely not the CL. So not a lot of action for a good goaly.
I might not make myself popular and I have to admit not having ssen to many games this young season, but I would not mind finding a replacement like buffon for Jens, period. Jens is not bad but has strange moments. He is no Seaman. And has cost us a few games.