Update support for GNOME shell extensions
IMHO it is a bad situation when you can only install GNOME Extensions via a software, but cannot update it with the same software. So you have to install a browser add-on for Firefox/Chrome/ium or use "GNOME Internet" (aka epiphany).
IMHO that's not a good practice. Any software you ncan install should also (as easily) be updated/updateable and not require more steps from the user.
As such I strongly propose to integrate the update process of GNOME shell extensions into GNOME Software.