Hi Ken and Wim,
Apparently there is this plugin. Haven’t tried. How to edit groups?
I agree that it’s hard to work with locked objects if you want them to look different than normal. If you set a colour in the DisplayMode for locked objects, the problem is that the objects appear opaque and if you have hatches mixed with lines, you only see one large surface.
This problem also arises for blocks. Everything is a single colour when you work in blocks with hatches.
There have already been several requests for a better way of handling the display of locked objects, such as every object 30% greyer, or a kind of black and grey.
The possibility of being able to set the parameters of locked objects in a DisplayMode so that they are displayed in another DisplayMode of your choice would be also very interesting.
––––
Indeed NamedSelection is another way of managing selections. But it doesn’t work as simply as Groups in on-the-fly selections.
And with NamedSelection the problems also arise. It’s even harder to modify a group made by NamedSelection because as soon as you touch an object you no longer see the other objects that are in the selection. You no longer have visual control of which part you’re working in. So at least with Groups you can work with the SubSelection and still see the whole Group.
It becomes difficult to follow 
But I think that the advantage of being able to enter a group means that you can focus on parts of a file without touching other objects, and compartmentalise easily and quickly. All the while keeping an eye on what you’re working on. This could be maybe done with Blocks, but subselection isn’t so easy, and unfortunately they don’t support the position of hatches RH-70320 or the grouping of the outline of hatches with their hatch, so they’re not really usable.
Best,
Pip