I'm interested in your view that this was a second string Juventus and that hey clearly "weren't up for it". We played Juve last December in the CL and lost 2-0. Of the team that beat us then 9 of the 11 appeared last night. Six of them started and and 3 were subbed, being replaced by 3 others who played last December. In total both teams used 5 subs and this was because of the extreme heat and humidity in the case of Juventus (as well as City) rather than to any lack of desire. Juventus will not have enjoyed any part of last night's drubbibg.
Your judgement that our defence is a shambles seems harsh and hasty as well. Our 'keeper has been an integral part of our attempts to build attacks when he gets the ball from Pep's first day at the club and it has worked and is working sensationally well but we do make (very few) mistakes, and Eddie made one last night. We can't find any other goalkeeper or defender who hasn't made a mistake in distribution. The second Juve goal was a good goal which exploited our high line. This can and does happen but it is entirely different to periods last season when even some mediocre teams seemed to able to run through midfield and our defence at will - Juventus managed 4 shots all night in the club world cup, not the Europa league.
Everyone knows that the conditions are unlikely to be replicated in our league season, that fatigue may have been more of a factor last night than it will be during our season and that City are a new side building connections and team play BUT If City can play consistently at last night's level we won't be far off the PL title if we don't win it. Last night's was a very impressive performance, not a defensive shambles, against a good Juve team.