Yes, having Haaland will increase the attacking power for the better, but if we flashback to last season when in the semi-finals and final of the UCL he couldn't do anything because his movements were always broken by Madrid and Inter Milan's back line, actually I don't think so either. Haaland can do a lot in the UCL this season, even though he has always been Guardiola's mainstay in the front line. KDB's return is actually more than enough.
Without Haaland, it seems that Manchester City will be fine in facing their opponents in the UCL. I think they will be successful again this season in reaching the final because Manchester City has risen from adversity since KDB managed to recover from injury. I also hope that Manchester City will win the title again this season. this is as perfect as they did last season, no matter without Haaland I think with the main squad which is currently more than enough in my view.
The round of 16 will soon start where they will face Copenhagen who managed to become Runner UP in group A which is quite difficult but they managed to escape with a surprise, I think Manchester City cannot underestimate them, even so they could make things difficult for Manchester City later.
By February the knock out stage for the UCL will kick off and for some teams, it'll be an easy slide through regardless of the notion of the strongest teams being the ones able to scale into this stage. City and Copenhagen would go against each other and it's very much clear that City would be the survivors.
Their key men are back and set to run and definitely that's enough charge to weigh down Copenhagen.
Yes, in their home ground, they may try to put up a battle but I'm certain that Manchester City will be capable to overturn them. They're way ahead of them in capacity and ability too. As always, the round of 16 will have as much fun as there can be in it and it's greatly anticipated. Preparations and games would definitely be intense too. Copenhagen as the underdogs would try their best but City would qualify for the next round.