Gaara was screwed over in that fight. Namely because of Deidara targeting the village. As a result, Gaara had to stop his assault on Deidara to use sand to not only defend the village, but also to draw away that very sand. This gave Deidara time, and it also drained Gaara of focus, time, and a fair bit of chakra. Also...Deidara lost an arm...hardly low difficulty.
As for a fight. Firstly, Gaara now uses flight with his sand which he never used origionally. While Sasuke can fly, this leaves him in the air, and can then be surrounded by sand. Not to mention Gaara can simply fly away just all the same.
Secondly, wherever he is, Gaara can create a desert just as he did against Kimmimaru...sand limit isn't a problem.
Kirin: You seem to be banking on the principle that Sasuke would use Kirin to win....there are a couple of questions here.
1. Time: Can Sasuke fire the fireballs into the air, generate a storm, and use Kirin before Gaara notices.
2. Position: Can sasuke stand in a position out of Kirin's path. Against Itachi he stood above the inpact zone.
3. Kirin: The storm was formed through the combination of a slowly buring Amaterasu ring in addition to his fireballs. Its entirely plausible that he'd be unable to generate enough heat.
4. Chakra: Sasuke has never started out his fights with anyone playing directy for a Kirin rush....so when he actually decides to use it...does he have enough chakra after trying to fight without it.
On to speed blitzing...many claim that Sasuke just rushes Gaara.
1. Gaara has already experienced a speed fight with Sasuke meaning he will likely initiate combat by going vertical...thus negating Sasuke's speed abilities.
2. Physical strain....Sasuke only had the speed he had because he copied Lee....with a completely focused and non-psychopathic murdering Gaara, can he actually get close to Gaara before the physical strain of Lee's typical style effects Sasuke. Even with a time skip, Sasuke hasn't trained his body to have that kind of speed....it would still cause strain on the body.
Raiton Jutsu
We have seen that with enough pressure, Sasuke barely managed to break through Gaara's sand. Additinally, he was actually stuck there and had he not shocked Gaara...he'd have been grappled. It is also good to note this was also a mind set of a psychotic Gaara and not one of a focused Gaara. Also, the surprise of bleeding for the first time also played a factor into why Gaara's spikes from the sand ball also stopped. Finally, Gaara was in the midst of transformation, and as a result was hardly even conscious. Its entirely possible Kazekage Gaara would simply have taken the hit to the shoulder for multiple piercings of Sasuke's body.
This means Kazekage Gaara could easily continue to focus on Sasuke...allowing the sand to swarm him.
We have not seen how, other than one instance of chidori, Raiton actually effects his sand at the present time.
Sasuke vs Deidara
This is also poor logic in determining why Gaara loses.
1. Gaara also had Zero intel...and had he not protected the village...had already taken out on of Deidara's arms (something Sasuke never did).
2. Sasuke had an elemental advantage in battle...so dispite how much more skill Deidara may have had, Sasuke's lightning style saved him on multiple occasions.
3. Sasuke honestly was a tad bit plot protected. Deidara notes and Sasuke seems VERY aware that he's out of chakra or EXTREMELY low....and yet out of nowhere he has the chakra to summon Manda...and a summon requires a large amount of chakra based on how we saw Naruto needing Kurama's chakra to summon Gammabunta during Part I.....following that, it also took Suigetsu timing his rescue almost too coincidentally....and even then Manda had still taken the Kill shot that would have iced Sasuke.
Gaara vs MS Sasuke
During the Kage summit arc....Gaara seemed easily comfortable against Sasuke....and his sand was capable of blocking amaterasu without effort.....and Amaterasu is ofter praised for being a seemingly "instantaneous" jutsu. Additionally, Sasuke attacked the roof rendering Gaara once more to protect those around him as Sasuke ran away to hunt Danzo. I'd say the fact his sand could block amaterasu would give more leeway into Gaara having apt defense for speed in addition to his flight.
I don't see Hebi Sasuke beating Gaara.....especially if Gaara has Shukkaku.