STH is there as a taunter, but also to feed TM to the rest of your team. Shore is a hard counter to Wiggs (eats the first shot) and Landakin (if he survives the initial onslaught). Imho, if you are running Wiggs yourself, it works best to use your 5th slot on rotation. I slot in Palpatine Shore or even Ackbar as the opposing team requires. My shoretrooper is G9. He usually dies before he can get his crit protection off. But by then it's usually 4v4 and I can usually win from there.