On paper, PSG might look better than Borussia Dortmund because PSG does have a better composition of players but that doesn't mean that they will be able to win easily against Dortmund because teams from the Bundesliga will always have their own motivation when competing in the Champions League and usually they will be very tough opponents. PSG could indeed get rid of Barcelona, but I think they got it after Barcelona made a very stupid mistake. If Barcelona had played with 11 men in that second leg, I don't think PSG would have been able to win against them.
PSG's goal was scored after Araujo received a red card in the 29th minute. PSG played quite well in that match but I think the red card that Araujo received had a significant impact on Barcelona's game. They cannot implement tactics and games as planned. And PSG was able to take advantage of that moment very well.
Dortmund are not a bad team, but I think they are on a bad run in their league. You are right that teams from the Bundesliga have their own motivation in the Champions league but I think Dortmund is one level below PSG. This is different from Munich, which can be said to be on an equal level with Madrid, although I still favor Real Madrid to become champions.