Keyboard Shortcuts to switch directly to applications
An ugly solution is to use xdotool to simulate the Super-[1-9] keypress. The xdotool command sequence can then be mapped to a custom keyboard shortcut from "System Settings" > Keyboard > Shortcuts". The commands to be run for the shortcuts are
Super-1
sh -c 'echo "keydown super sleep 0.2 key 1 super" | xdotool -'
Super-2
sh -c 'echo "keydown super sleep 0.2 key 2 super" | xdotool -'
Super-3
sh -c 'echo "keydown super sleep 0.2 key 3 super" | xdotool -'
I use AutoKey to map keys for switching to Terminal. A short demo is here. It's very easy to use.