Alternatively, if you're so used to clicking on the panel to switch workspaces: GNOME has this feature, too, but it's not enabled by default in Mint. It takes up quite some space in the panel and I guess it makes sense only if you use two panels - top and bottom - commonly found in other distros using GNOME.
Right click on the panel (a.k.a. task bar) and choose "Add to panel" - you should see the Workspace Switcher applet there.
War does not determine who is right - only who is left. - Bertrand Russell