You're spot on imo.Yes, that's true but also with DDG inability to participate in the build up phase and constantly hoofing the ball up the pitch leaving attackers to battle for those 50-50 balls isn't something that any player from the offensive line would appreciate.
Although I agree 100% that chance creation wasn't a problem last season but finishing, I just have a feeling that the source of those chances isn't something you wanna see from a top side and that we should look for something that is more consistent in order to reach the level we are aiming to. We heavily relied on fast breaks and Bruno-Rashford connection and I can see having a more possession based system, in which goalkeeper is crucial, can lead to not better chance creation but creating chances of better quality consistently and from a variety of different sources on the field.
It's not just the goalkeeper of course, but with adding players like Mount and possibly Amrabat to already a very good group of players we could really start to build something possession based, and Hojlund as a new #9, despite not having flashy numbers at Atalanta, could really capitalise on that. By saying that, this also does not exclude fast transitions as extra but not primary source of our chance creation.
I agree with you that having a goalkeeper like Onana can't improve your chance conversion, but it can help in attacking play by building something that at the other end of the pitch will result in a high quality chance. Thank you for this nice football related conversation, something that's rare to find these days.
Ps. You are right about Onana and his commanding qualities, it's better safe than sorry in terms of prevention of conceded chances.
Also just to add to your post, with De Gea in goal, we invited the opposition to press us high aggressively. And those teams who were good at pressing us high would get a lot of joy by pressing us high with the GK being a non entity regards helping the team play out of the pressure that was being exerted by the opposition. Hence we would hit it long and lose control of a sequence of play that we were in control of.
Onana has the ability to create danger for both a high pressing opponent aswell as a opponent who is looking to press in a mid block. Pressing high against Onana opens up a real possibility of the first line of pressure being by-passed, and a mid block team will leave enough space in behind for Onana to come further up the pitch and hit the space in behind Rashford or Hojlund to run into.