Instant feedback when opening an app
Starting an app can take a while, so after clicking the icon in the app grid you currently see the previously active app first, and then when the app starts it overlays that app. This can lead to thinking that opening the app didn't work, so I've found myself going back to the overview and try to open it again.
Ideally the app window should open immediately (like on iOS for example), even if it contains just a spinner for a few seconds. I'd be interested in a general GNOME-wide pattern for this, but there might also be short-term solutions we could do on the phone only, since we only have a single fullscreen window at a time. I think Endless has something like this, where they have a separate fake window containing the app icon and a spinner, which closes when the real window opens.