Anything can happen. Even a team you did not expect to win or even perform well will surprise you. That is how football works, and for that, even Chelsea can win the UCL.
Football cannot be predicted every time successfully, we ha e to try our best, because these players and their respective teams are also trying all their best to ensure that they emerged for the best and to the last, the UEFA Champions League title is what every team has been aiming, same also, we can't tell who may win for this new season, until we see how far they all can go in it.
One reason I believe is making many think one team will win over the other is mostly because they have seen that these teams may be doing well in their various domestic leagues and probably have fantastic squad but even with all of that, it will be best to wait till the season kicks off then we for sure are going to see who has better potential at the champions league trophy over the others, the champions league will start weeks ahead and so predictions now may just be based on assertions.