We all know that the villages' armies have joined together to fight Tobi and his Moon's Eye Plan.
Here is an interesting statement made by Pain - "If you don't share someone's pain, you can never understand them. But just because you understand them doesn't mean you can come to an agreement."...
So Gaara's weakness is most likely water, so how would he compete with somebody who is entirely water? I think there are very few battles Gaara could lose, but this might be his Achilles Heel. Opinions?