Tassadar's special victory always was the hardest along with Aldaris'. That hasn't changed, and the Leadership cards don't help Tassadar much.
In stage I, I would never ever go for the special victory condition. It is nearly not planable if you will be able to hold that many areas with units as expensive as are the ones Tassadar is forced to use, and you want to get rid of elements you can't control. So the likely variant of Tassadar is the CP victory. For this, he can go the boring path of having more minerals (to pop out more zealots, for example), or he gets the Warp Gate. Like the Overmind and the Cerebrate this way he's telling every one he wants to be attacked. But hey, the Warp Gate is much more powerful than Aldaris' stupid Conclave Fleet. Why flying when you can beam? You can reinforce though the whole galaxy, which becomes extremly nasty if you get your hands on one of those reinforcement event cards and your enemy left an area on his home planet open.
In stage II, Tassadar may choose between two heroes. Despite that the Ganthritor, being a carrier, may be the obvious choice to some, Zeratul is very cool in his own right. As long as you control where he fights, he is nearly not vulnerable and you destroy 2 ground units per battle, one even before skirmishes are set! That way you can destroy up to half of the enemy's force with one single heroe who survives the battle no matter what. Of course, the Ganthritor is very cool to bring down the Overmind or the Cerebrate. Or other things you won't attack in force.
In stage III, you have two options. I can't imagine a situation where I wanted to place 8 transports, especially since the game only provides 7 and at least two of them WILL be on the board where I need them. This card rates highly for the weakest stage-III-card in the game. The other one is much more important, since she allows you to kill a high templar to sweep empty the most defended area of an enemy. Especially nasty when Mengsk chooses before you. "You got two battle cruisers? Well, can't see them anywhere."
Tassadar is a harder faction to play, I find. In the vanilla game, he was easier than Aldaris, but with Brood War, this changed.