The growth in Tizzano's game has been great to see and he's putting pressure on McReight, but he has still has a way to go to displace him. Aside from the link play that has already been mentioned, Tizzano needs to find a way to bring the parts of his game together in one performance. For all his increased attacking impact this year his ruck work has taken a back seat - he's not getting over the ball anywhere near as much as any of the other 7s in Australia (or some of the backs like Daugunu) and he's not making as many dominant shots as last year, where he previously lead the comp for tackles resulting in a turnover.
He does have this in his game, but he needs to keep showing it - I don't think the extra attacking threat from him is worth much at all at test level if he's not nailing the core role around the ruck