At present, the fact of Local View activation is signaled only by a small sign in the upper left corner of the 3D View Editor. This feature is quite important and should be much better visualized. For example, by dimming the rest of the model in the Viewport and dimming objects outside the Local View in Outliner.
Thanks to this, objects would be separated from other elements of the scene, but would remain in the context of the whole. Transparency should be controlled via Viewport Overlays within a range of - lets say 75% ~ 100% - so that one can set transparency = 100% and get better responsiveness for complex scenes.
Standard view of all elements in the scene:
Local View now:
Improoved Local View proposal: