We might be able to have our cake and eat it too.
If forced then clearly Joe is the only choice primarily because of his age, but Shay Given is still quality and a club that has our aspirations needs two quality keepers like Chelsea have managed for years. No more signing reserve keepers from Sunderland ta (however good he turned out to be).
There is a selling job to be done on Shay.
Option 1 - take the short term view and move on for first team football at another top side. This may only last a couple of years before you have to do a Jamo and move to some godforsaken lower league side with ambition but far lower salaries and what happens after that????
option 2 - stay put at City and be regarded as the joint number 1 this season getting plenty of games in both league and cup. Accept that Joe is the future and work with him as we gradually transition him ove the next season or two while you still get plenty of games and build up your coaching experience as well. This way you can still be with City for the next few years, say a 4 year contract. on the same money as now playing and coaching and finish your career at the top on more money with badges instead of bristol or summat.