Quite an interesting question Sneha..
Maybe he found loopholes in the script, maybe HE didn't find the story exciting, maybe he didn't like the way it would be projected...there are a lot of maybe's ..but all i can say is Rajeev comes across as a very technical chap..he sees all the things and only then decides to sign the dotted line...
Me thinks he was scared the entire focus would be only on Kanchi and he would be reduced only to a side artiste??
But anyways i alwyas trust his decision he's a wise guy..i'm sure he had a point..
Haan even i feel he cud generate a good chemistry with Kanchi..she's sweet