Comment 12 for bug 1061852

For those still facing this issue, here is the workaround that I'm using.
It's based on my previous comment:

I've added the command "/usr/bin/unity-scope-loader applications/applications.scope applications/scopes.scope commands.scope" to the auto-start programs, with a delay (30 seconds in my case).
The applications scope used to take 10+ seconds to load for me, now it takes 3-5 seconds.

I've attached a ".desktop" file.
If you want to use this workaround, download the file and move it to "~/.config/autostart".
The command starts after a delay of 20 seconds by default (after login). If you want to change it, open the file with the text editor (open the text editor, then drag the file into the editor) and change the "X-GNOME-Autostart-Delay" field.
You may also want to open the auto-start configuration program from the Dash to check if it was really added and is enabled.