Even if City beats RM in the semis, how is City a more difficult opponent in the final?
RM is not a team known for losing UCL finals, both are tough, but if i were you i would want City, actually.
It's to do with the approaches, Madrid is a much more favourable game for Inter.
Madrid play the knockout ties the same way every time, cede control and wait for transitions on the counter to get ball to Vini and Benz in space. By and large it works well against likes of City and Liverpool, who although different, are both aggressive in their own way and get a lot of people forward and are happier to play high lines.
Against Inter it isn't the case. They are a slow buildup, 5 back Italian bus in these types of games. They are going to sit back compactly and try and build up slowly when they have it, who has done that with a lot of success vs Madrid this season? (Barca!)
Madrid also have been really poor in the league mainly due to failure to break down parked buses and deep lying teams who put initiative on Madrid to attack and try and find space not the other way around.
Inter has a solid defensive structure tactically but also has some technically proficient midfielders who can hold the ball and frustrate with it when needed.
City are better against smaller, defensive teams because they use a positional play approach, which is the best for breaking down deep blocks, it stretches the defensive line out and ensures complete dominance of the ball and game, because you're using every space on the pitch to attack and unbalance them, as opposed to this 'relationist' approach where Madrid putting 3 or 4 players on one side to one two with each other and not utilising the whole pitch.
Of course, Madrid is going to be the gigantic favourite for pretty much anyone predicting that final, but I think Inter would be in with a great chance.