Maybe if you could give some examples of open world games with streamlined level design, it would be easier for me to comment on that. For now I cant, because open world games inevitably lose their streamlined nature by requiring to move through large expanses to get to the next point, or side quests that take you off the main story.

AndI dont think Borderlands is a good example for what I am saying. Just because it has those more tight areas doesnt really change the fundamentals of being in a large open world and everything that comes with that. 

While I think what you are saying has potential, I dont agree with that in the context of GoW. Every single in GoW is about going straight for your goal. That is pretty much the mindset of Kratos and this mindset is explorated in how the environment works. Kratos wouldnt be doing all these optional side quests that take him away from his goal. This 'openness' not only makes little sense narratively in the game, it makes little sense in the context of Kratos as a character. This is pretty relative to ppl saying that you should have a choice at the end of TloU. The answer is no you shouldnt because you are playing a ame with a defined story, a defined character and all the structures that come with making that connect. The same applies for GoW. irrespective of whether you think the story or bulidng of Kratos is good or not, the game design mimics the character and the narrative taking place. GoW is not about diddle daddling doing littles things that dont connect to the core objective at the time. Nor is Kratos someone who would do that.

Which what makes an open-world a bad idea as far as I am concerned. What GoW needs is to be wide-linear. This gives you options to tackle scenarios in different ways or take different paths that lead to the same destination (but are not side paths or side quests), just a differnt route taken. This way SM can still work on creatiing their set pieces within definied contexts instead of trying to tax their game engine with an open-world aspect that will just run up short to the type of games they make.  In this way they can still keep the sense of urgency that underlines the story of each GoW as well as what underlines Kratos as a characer.