The Real Madrid vs Manchester City match is the most interesting, but the Milan derby is also interesting. Manchester City may be lucky as they are away from home in the first leg, so they have a chance to do better at the Etihad in the second leg. If City lose the first leg then I hope it won't be too big on aggregate, but discussion of the result seems premature.
I'm favorites Manchester City to impress in the semi-finals and qualify for the final. But I think they really had to fight hard to beat the reigning champions last season. Madrid are still the best in the competition, but that doesn't mean they will be as lucky as the previous season to qualify for the final.
Apart from that, indeed in this case Manchester City is still very much the favorite, it's just that they clearly know what mistake they made last season by being too complacent in the midst of conditions the match had not ended.
If indeed they do it again at this time then it is certain that this will be very bad again for them, especially if they don't underestimate Madrid even though later they will be superior because it will destroy them again.
I don't think it's right to talk about favorites in the match between Manchester City and Real Madrid. The better team that day between the two teams wins. Both are among the strongest teams in today's football world. Real Madrid is last year's champion. We will watch two very enjoyable series in these matches, and we are lucky in this regard.