It is all about not underestimating their opponents in this round. Bayern, Manchester City and Real Madrid are the favorites in all those games, but there have been surprises in the past. I would be no exception if one of them gets under pressure, but since it is two games to go, I doubt that any of these teams would falter. I rather expect a few superior games by those teams and then we will see what the next round brings regarding the drawing.
We expects our favorite team to come our victorious in every match played but it's quite important these clubs doesn't fall out of track. UEFA Champions League is definitely not a competition for mediocre teams, the title race is only among the best clubs. We have watch and observe the outstanding performance exhibited by these teams, none of them holds back because striving for good results have always been the ultimate goal. You're correct, these elite clubs are opportune to be on the lists because they've become one of the very tough clubs, proven themselves.
Uff, maybe it is a competition for teams that seem to be mediocre but have an ace up their sleeves. If you remember how Sevilla did in the Europa League or how once Porto did when Mourinho was the coach, these teams were nowhere on the planet considered the favorites in these competitions, but they won it. Statistically you are right, the Champions League doesn't really give good reasons to think that an outsider would win the competition in the end, but I still think that there is only a vague definition as to who counts as a a non-favorite team and a favorite team. This season there are a couple of teams that I am not sure about what to think of them. But I will find out soon and that's what makes this season exciting once again.