I agree with this ^
EDIT: there is one other thing that noticed everyone forgot to mention.....at the time, Gaara...was the 1 Tail Jinchuiriki. Without the village needing to be protected, Gaara could have really let loose and let the one tails loose increasing everything he already displayed during the Deidara fight. I agree with others that in order to win this, Sasori would have to exploit the safety of the Sand Village.
It's still a perfectly viable way to win, but remove the village and Sasori (and Deidara) are screwed. .....Well until that 3rd Kazekage puppet is released then I wonder....