And sometimes you don't have the energy to storm and don't have a fresh templar available. I played a game the other day, and when scouting the front saw like 6 marines and 3 marauders. I teched to storm and started making HTs, and when he got to my base there were 2 thors in the mix. HT's and Immortals were a great choice(designed to kill marines and marauders, but coincidentally very good against thors too), storm the army and then feedback on the thors and medivacs when I ran out of energy. Sure, it was a very situational play, but it was a handy option available to me.
Unfortunately I still lost that game, the pathing was really bad on blistering sands and half my army decided to retreat into my main like I wanted while the other half decided to advance out of my natural towards my back door, taking the roundabout route and following his army into my base. So both halves got decimated unfortunately. But the point is, 100-150 or so damage on a couple of thors can mean the difference between winning a battle and losing it, and now that option is no longer available.
EDIT: Syth, game five was awesome, Nani rushed for a hidden Dark Shrine and decimated Morrow's SCV line in both bases, was up ~50 harvesters to 15. It was wicked awesome.
EDIT 2: Holy shit crazy game 6 Marauder micro. Just roflstomping the gateway units all day long, awesome retreat and push from one side fo the map to the other. Crazy, crazy game.