We can't say much at this point but I'm pretty sure that City won't win it again. They need 1 bad game in knockout stage and they will be out. Going 2years without bad game it's really hard and City does not have legacy of Real M to do that.
What gives you the impression that Manchester City won't be able to accomplish what Real Madrid did by winning the champions league back-to-back by the next season? Manchester City currently possesses the best team that can defeat any opponent. The only thing I am aware of that would prevent Manchester City from winning the Champions League by the next season is if they sold or loaned some of its important players to other teams, or even if some of their players sustained major injuries that would have a negative impact on the team's performance. Apart from that, I don't think anything can stop Manchester City from reclaiming the champions league title.
I am happy that you know that injury can play a major role on the life of a player and a club in their performance. This is why it might be impossible for Man City to win it again next season even with the same players. We saw how injury crippled Man united performance and some other good clubs performance,which made it impossible for them to achieve their goal. Man City was very lucky,that they didnt suffer from injury this season which made the club and players stronger. So let's stop thinking that next season will be the same as this season. Changes is constant,who on earth will believe that Chelsea will perform poorly this season. It is hard to look into the future but we can also think that it is possible for things to remain the way that they are.