It reminds me of the last Champions League playoffs, when City and Real also met quite early and there was also a lot of talk about how they met too early and that the winner of this pair would eventually become the champion. Obviously, it has always been very difficult to compete with Real, now little has changed, and although it seems that Real is not so strong now, they will always remain the favorites to win the Champions League.
Last season, they met each other but there was no playoff matches last season. This season is a first time, with a new Champions League format, and it gives chance for Manchester City and Real Madrid meeting each other in very early playoff matches.
Playoff matches mean they will have to fight and eliminate their opponents directly to go next. Both Manchester City and Real Madrid consider their main target in Champions League is winning it, so they will not want to end their adventure in this season too early after playoff stage. Obviously, their appearance in later stages will make Champions League more exciting, but unfortunately only either Real Madrid or Manchester City will be eligible for a next stage after playoff stage.