I am going to go on a limb and say that Real Madrid will not win UCL this season as well. They are not going ot be as bad as last year, because they had many injuries last year which caused them to be worse, they will do better at group stages at least, and depending on who they face afterwards, I bet they can go even further, but they won't win.
Because every season, the best team in the world usually ends up winning, and that means, even if you are a lucky team with a good draw luck, facing easier opponents and go to finals, you will still lose at finals because the best team wins. Rare cases of smaller teams winning, but that's very rare. And at this moment Real Madrid is not the best team and PSG looks like the better team, even few others.
I think so too, and I believe it's due to the numerous injuries, but Xabi Alonso won't be able to make Real Madrid much stronger in his first season. Xabi Alonso isn't a coach with experience in major competitions with high pressure, so that will have a significant impact.
In the Champions League, everything will be different. The competition for the title is quite fierce because every team is ambitious to win the UCL. I think that's the reason.