I also think it's a bit too early to start talking about it, also because the transfer market has to take place and some nations could place additional teams on the list.
For sure the winner take always the spot for the next year... let's see how it proceed but anyway it's always "a long battle" up to the finale...
Why is OP in a rush when we still have the fresh memory of this season finals and we are still discussing on it. Moreover,there is already a thread on UCL which we have been discussing on that the OP,do edit whenever a new season starts. Personally,I don't have anything to say because I can't look into the future,transfers hasn't be made and we don't know how strong this clubs will be. It is when next season starts that one can have a proper insight of the league. Man city won't be able to win back to back,let's no deceive ourselves.
Why do you think that Manchester City cannot win the Champions League back to back, it could be you that is deceiving yourself here. Just look at last season and season ago Manchester city is the Champions league team of the year for upto 3 consecutive times if I am not mistakakikg. This shows how good the Guardiola team has turned out to be. They dominated the CL team of the year and not many of them will leave the club this season. So it is expected that Manchester City will get to the finals and win the Champions League consecutive.