PSG just won their first Champions League title, left with the same players in the team, i expect them to be a difficult competitor but chances should be slim even if they will make the league difficult for other teams to progress, they might be kicked out during any stage of the finals before the main final. I have the feeling that if Barcelona can make it to the semi final, this time around might become the next Champions League winners, with their performance so far they deserve to raise the title.
There is no need for PSG to make big changes in their squad. Luis Enrique's system and the current players are already more than okay for a back-to-back.
Recently if you have noticed, the only team managed to beat them out of a tournament is Chelsea. I would love to see them facing each other in the Champions League this time...
And of course I can't overlook the fact that English teams in general made difficulties for them last season.