I believe PSG is an overall better team than Dortmund and should easily win over them. PSG are the top team in Ligue 1, they has defeated Barcelona in the quaterfinals, which is a second team on La Liga. While Dortmund is the 5th team on Bundesliga who defeated Atletico Madrid which is the 4th team in La liga. Every stats shows Dortmund have an easier path to semifinals.
Having better squad did not help PSG to win Dortmund in group stage and it is not good for their mentally support before two semi final matches. I know big difference between group-stage matches and semi final matches but their previous two matches in this season, are good evidences that Dortmund are not a weak opponent for PSG. PSG in theory are stronger but they have to do a lot of things to beat Dortmund in semi finals.
The Munich vs Real Madrid would be the ultimate battle. The winner of this high stake match would be the favorite for the championship title.
Bayern Munich and Real Madrid had many matches with each other in the past and they are very traditional successful clubs in Champions League. It's hard to predict the winner between them but it's interesting to see Bundesliga have another season with potential to have two clubs in Champions League final match. Many years ago, Bayern Munich met Dortmund in Champions League final, will it repeat this season?