The truth is, Khali will only be champ until Unforgiven most likely. Survivor Series the latest. After the finish of the match at Summerslam, I'd expect a Khali/Batista rematch, this time with some stipulation added to hopefully make the match more bearable. Batista would probably win then, defend it in October against Khali, and then fued with a returning Edge. I don't see Khali really lasting as WHC much longer because he really isn't over. The crowd was DEAD for his match with Batista, and I promise you, it's not because of Batista. Khali is boring in every aspect of the business. His in ring skills are terrible, and make Vince McMahon look amazing in the ring. His mic skills are even worse, and his translater is a terrible mouthpiece for him. Plus, the few moves he does do, he does terribly. The fact that the WWE writers are afraid to have him do LIVE matches is bad. He's on Smackdown for a reason. Editing ability. They avoid lengthy matches on PPV's for him because of his ability, or lack there of.
A rematch with Batista would probably be in a cage, or be no holds barred, simply to add the elements of big spots to the match, with Batista winning after dropping Khali in a big way, either off a stage, or a big Batista Bomb somehow with a cage, or through tables or something of that nature.
Khali could get over big if he had a good mouth piece, however. Had they had Paul Heyman be his mouth piece, then he'd have been a huge success, and the fans would hate him more on his gimmick than his lack of ability. Heyman has the ability to get fans to hate him/people he manages. Look at Rhyno, Lesnar, etc. He managed them and they were over as heels.