I know that in general we don't apply many patched downstream to Gnome except for some interesting features (like for gnome-terminal for example). In this case I was wondering if installing an extension or simply apply this patch from upstream (but that they won't apply):
Personally, I would suggest to apply the patch as it looks really easy to keep updated, also default would still be upstream one, and people could still change it from dconf-editor or default settings on their setups.
From my point of view I don't quite understand upstream logic on this as, at least with default Gnome workflow, wallpaper is rarely seen when using the computer normally, as we don't minimize windows, and I don't think people will switch to an empty workspace simply to see the wallpaper :/
In my case when I see the wallpaper is when computer is locked (it is also the same logic as in our Android or iPhone smartphones... that wallpaper ends up being more seen in lock screen than when using the phones)
So go to https://extensions.gnome.org/extension/2935/control-blur-effect-on-lock-screen/ and hit the toggle switch to ON? :)
Yeah, is the one I am using now... but reading the bug comments, it seems it is currently working "by luck" as it seems that extensions are not supposed to work in lock screen. I am also unsure if it will break in the future... also, relying on the extension, we rely on someone to maintain that extension, while the patch looks so simple that I think it has less changes to break and to need porting in the future.
Of course we can go for extension route too... but wanted to point that the patch exist from upstream and is an alternative
Ah, one downside of the extension that I just noticed is that it doesn't work after resuming from suspend. I need to unlock after resume and then it gets reactivated