I would appreciate multiple viewports.
Simply saying “just model in 3D” doesn’t make sense. Many design processes are better done in 2D, especially when you’re working with 2D Plans provided by others. Try analyzing vehicle tracking curves or designing electrical layouts in 3D to see what I mean.
For interior design I can appreciate how moving around inside a 3d room or building can be difficult …Tight spaces require a high field of view which distorts the sense of distance and space. Objects in the foreground get in the way of objects behind them. (wireframe and xray are good but get very messy on complex models)… This is problematic also when collaborating with other professionals who aren’t used to navigating in 3d space.
Flicking between 2d/3d scenes all the time is a bit cumbersome and interupts the ‘flow’ of the designer.
So yes I think there is a valid use for modelling in 2D and 3D at the same time.
I would also like to view things in different styles, eg Sketchy edges and textured face view, at the same time.
I totally agree working in 2D is annoying and that documenting paper drawings is stupid and should be abolished from the world, but that day hasn’t come yet.