Well, if one Akatsuki could capture Gaara, and don't forget, Deidera was having trouble NOT killing him, then defeating the rest of the team of Akatsuki without his bijuu would seem very difficult. I can remember in past encounters between Gaara and his opponent, it's always been commented that the sand he carries around with him is mixed with his chakra. If we take that to mean his own, and not the bijuu's then Gaara will still be able to manipulate sand, though the effectiveness of it without the massive chakra boost is yet to be seen. One thing technique that Gaara would definitely lose is the sand's automatic defence. Unlike his sand control, which can be argued to require chakra alone, regardless of the source within Gaara, the defence sand moved without his conscious thought, and will protect him against his will. We can therefore deduce that it's not under his control, and losing the bijuu will also result in a loss of that technique. Not sure about the Shukaku absolute defence move, or the Spear of Shukaku move. (Is the spear even in the manga? We saw it in the last filler arc.)