Everybody here knows what happened to the Sand Trio at Konoha's Invasion. Kankuro gave up on his fight in the Chunin Exams, and was defeated by Shino later. Temari was 'overwhelmed' by Shikamaru, without give serious damage to him. And Gaara had his 'absolute defense' pierced by Sasuke, loses the control, free Shukaku, and is defeated by Naruto. The question now is, did they used all they had at Konoha's Invasion? The answer is NO. From the beginning all they tried to do was not call much attention to not reveal his plan. At least Kankuro and Temari were against the killings of Gaara that, furious and wanting only the blood of his opponents, proved weaker than he really is. After the invasion of Konoha, less than two months passed before the triumphant return of this trio to help Konoha, but they returned with new techniques, and high-level. Considering that it was required time for Gaara recover from his injuries in the fight against Naruto and the Sand Village recover from the loss of his Kazekage, to re-stabilize, I believe that it was not possible to they learn such new techniques in this short time period.
See the techniques:
Appeared with another puppet out of nowhere, and mastering completely its movement way. Even to a skillful puppeteer, master a new puppet must not be something to do in less than two months. And he 'plays' masterfully with his 'doll'. Kankuro also says that Karasu is made to interact with Kuroari. So how could he come up with combo strategies with the two puppets in such a short time? We know that in the three years that passed until the Shippuuden, Kankuro dominated just one
other puppet. If he could move from one to two in less than two months, in three years he would be able to use more than three, I believe. This makes it clear that Kankuro already knew the mastering of the second puppet, Kuroari. So why he did not use it? Because the technique he uses with it is deadly, it's cruel. The technique that unites Karasu and Kuroari
is extremely deadly, and death was prohibited in the Chuunin Exam. Not wanting to draw attention to his plan, Kankuro used only Karasu, and was very good doing it.
Same case as Kankuro. Temari didn't wanted to kill. This was clear in her fight against Shikamaru. If her intention was kill him, she would have used a stronger wind, capable of cutting the tree Shikamaru was hiding with him going together. Moreover, Temari came up with a Kuchiyose
. If she wished she would have used the Kuchiyose on Sasuke, that pursued her, but that would reveal its position in the forest in the midst of her flight, and easily find the other Shinobi. Besides, she knew that Gaara would kill her if she killed Sasuke. Think of it this way now. To learn Kuchiyose a shinobi must sign a blood "contract" with the animal invoked. With that, he needs someone who can make that same Kuchiyose. However, it was not disclosed at any time to anyone who taught Kuchiyose to Temari, which makes me suspect that she already knew the technique before, after all, the only person in Suna who would have the ability to teach this technique to Temari, according to the own manga or anime allowed us, was the Kazekage himself, his father. Thus, if the Kazekage was killed by Orochimaru in advance, how Temari would have learned this technique? Before going to the exam. (obviously this is just my assumption. How was not revealed in the anime or manga, is free to take assumptions). Summarizing, Temari already knew Kiri Kiri no Mai
Kuchiyose before going to the chuunin exam.
It was clear that Gaara had bloodlust. All he wanted was to see people dying in front of him. So why would he use Shukaku no Tate? In this technique, Gaara creates a 'doll' of Shukaku using minerals from the ground, creating a much tougher defense than all his sand together. Not even the bones of Kimimaru could pierce the defense. But, being a defensive technique that relies more on strategy, why would Gaara use it against an enemy who he wants to see dead? He was out of control, unable to think of any technique that does not involve the blood of the enemy. What about Quicksand Waterfall Flow
? That giant wave of sand. If Gaara used it at the Chuunin exam, against Sasuke, who wouldn't have place to run because of the arena delimitations, Gaara would have a battle won. But he does not use his sand to do this technique, but rather, the sand of the ground. Thus, if he killed Sasuke that way, where would be the fun? Where would be the blood? How would he feed his sand? After that, he was wounded and lost the control completely. Therefore, he could not do this technique that requires soil preparation and a good amount of hand seals. Gaara did not use all his skill in the invasion of Konoha, and was actually stronger than he was when he came to help Konoha ...