Actually all the top teams in Europe look weaker compared to recent times.
Barca have poor depth in all areas, an average goalkeeper and slow midfielders. Busquets especially looks in poor shape, Dani Alves is gone etc. City exposed their glaring weaknesses. Even when they lost 4-0 to Barca they threatened them greatly until Bravo had a brain hemorrhage.
Real Madrid look pretty unconvincing overall. A 3-3 draw to Legia last night after leading 2-0 is pretty preposterous.
Atletico will probably go far again but they need Griezmann to carry them with his goals. So far he hasn't been great this season.
I think the door is open for one of the underdogs to win it this season. Possibly PSG, City or dare I say it?