I'm not doubting that the UEFA Champions League will not be interesting if Real Madrid or Manchester City are knocked out in the quarterfinal. The interest in watching the UEFA Champions League will reduce because Real Madrid and Manchester City supporters will not want to watch the UEFA Champions League again when Real Madrid or Manchester City are knocked out.
Don't worry because only one of them will be eliminated in the final quarter. 
Yes, it's quite annoying to see these two favorite teams always meet early. Last season Manchester City and Real Madrid also met in the semi-finals and only one of them went to the final. Even though I'm sure every season we expect these two teams to be in the final. But in reality, one of them is always eliminated every season. But I personally still think the UCL is very interesting even if one of the two teams is eliminated. But if both of them were eliminated early maybe I would also be a little disappointed.
But actually, even though this season is not finished, I am also starting to see the potential for the UCL next season to be more interesting. because it looks like the representatives from Laliga will be a little different next season. Because maybe Girona will also be there next season in the UCL. And from the Bundesliga we will also see Leverkusen coming to the UCL. Well, this will add to the excitement of the UCL next season. But this season's UCL is no less exciting. Because some unexpected things have happened. Like the elimination of all teams from Italy in the round of 16 and qualifying groups. One thing that was quite disappointing was that the meeting between Manchester City and Real Madrid was too early.