If you install an app that's missing some lib, segmentation faults, clashes with SELinux etc. and launch it from the desktop or panel the app will just silently fail. You wont know if it's just taking long to start or if it has crashed and for what reason. To actually see that you have to launch the app from a terminal and look at the output.

I think gnome should display an error message when an app fails to launch with the output from the app. Something like:

"Application X failed to launch. This is the output from the application:

/usr/bin/someapp: error while loading shared libraries: somelib.so.4: cannot open shared object file: No such file or directory"

The output might be confusing for a novice user so perhaps it could be hidden behind a button "Click here for more information" or something, but the important thing is that an error message is displayed so that the app isn't just silently failing leaving the user to wonder what has happened.