Any position modifiers (other than Urgot's ult, that I can think of) cannot be cleansed, QSS'd, or W'd out of. Knock ups and knock backs still work. Blitz, Janna, Ali, Poppy, Vayne, J4, Cho'Gath, Darius, Jayce, Gragas, Lee Sin, Lulu, Malphite and a host of other champs can still CC Gangplank. If you really wanted to be troll, try running that build on Olaf. With R at level 3, Olaf is literally unstoppable for 8 seconds.
Edit: Skarner's Impale is another position modifier (assuming he runs with you stuck in his ultimate) that can be removed.