I agree line style should be controlled in SU.
I think it’s important to try to separate modeling from presentation and have the two programs have clearer scope, and not have them overlap too much. This overlap in responsibility means one person can’t open the model for additional design work while another person locks it for working on the presentation, as the presentation person (as of now) needs to adjust scenes in the model. More importantly the overlap is confusing as the programs don’t communicate any workflow to you. Sure, multiple workflows can exist, but a good UX design should gently nudge people into doing things the preferred way without external teaching, just from the design itself.
All that said, line styling is semantic and not “artistic” choices you do while working on the presentation. The styles carry a meaning that makes sense to define already in the model, while e.g. the exact camera locations, section cut placements and so on are choices that makes sense to do in LayOut, based on how the viewport looks together and how they fit into a paper and other things.
When doing the presentation you can realize this text is too small so I make it bigger but then i need to move that viewport over there and get rid of that other viewport but then there is nothing showing the staircase so I move the section cut slightly in this other viewpoint. Those are all choices done when in the presentation mindset. You don’t typically thicken the section cut line of the ground in one specific viewport to visually balance a balloon in the sky. I’d argue the line weights is a chose you make already when setting up the tags in the first place, and likely something you want to re-use using a custom template.
The whole override mental model also gets confusing when there is no corresponding property from the SketchUp model to override. And it gets a bit painful when setting line weights means Tags as a whole is regarded overridden and the link to visibility from the model is severed, when you never wanted to touch that link in the first place.
Also I don’t see much reason to control line weights on a viewport basis. I can only think of two uses of line weights. Either you make a drawing and want thicker lines for load bearing walls and thinner for glass, furniture, scale figures etc and you want these consistent across viewports, or you make “3d view”, and want just a single consistent lien style throughout.
Where we are now I think the best approach is to expose line weight in SketchUp, together with stipple and maybe also color in one single consistent location. Then you could set up walls to have one width, glass another, furniture another and scale figures yet another, and use those styles consistently in any viewpot created at any time.
When modeling you’d probably disable the By Tag Edge Style to reduce noise, but you could use it as a preview in SketchUp and to check everything is correctly tagged.
The override option in LO is kept to allow for early adopters to keep using it the way they are used to, and for fine tuning in rare cases.