Salute to Pep Guardiola if he can bring his team to defend the Champions League title because it is not an easy job and this time Manchester City's competition will still be with the same team, there are Bayern Munich, Real Madrid, Inter Milan and several other teams that cannot be underestimated just like that because they still have the ability to be competitive competitors in this tournament, but the teams that are their competitors this time are progressing quite rapidly, such as Real Madrid, Bayern Munich and also Inter Milan, so if Manchester City meets one of these teams before the final their struggle will be very tough, and I don't favor Manchester City as champions here for the second time even though KDB has returned to play but Real Madrid and Bayern Munich look like they have a better chance of becoming champions league champions this season.
Yeah truly the competition on this champion league is actually getting really more tougher considering the major clubs that are currently on the race, although if Manchester City has putting the performance they had last season to this season they would have likely win this champion league again but however there performance and determination this season champion league seem a bit weak and perhaps it was only during the early time of this season that Manchester City was really pushing on the champions League table but there consistent was not enough and they began to lose form, but however with the arrival of Kevin de Bruyne Manchester City has peak form but however I don't think they stand a chance to win the champions league again this season.
So perhaps just like you said I'm also looking at Bayern Munich, Real Madrid and Inter Milan as the main candidate of the champions League this season but most especially Bayern Munich and real Madrid because they are better than inter Milan in times of performance but if real Madrid manage to reach final I think they will have an upper chance of wining the champions League because they have a good history on champions league league especially the finals.