The film's director and producer have realized that killing all the leading stars of the film wasn't such a good idea after all because it has had a negative impact on the film's performance at the box office. This is also one of the reasons why the Telugu distributors are hesitating to buy the dubbing rights of the film.
'Vaana' had a tragic end and it flopped. The industry isn't interested in risking another film with a sad ending. So everybody is now wondering if it would be a good idea to reshoot the entire climax scene and leave some people on the screen alive.
But the problem is- the film already took its own sweet time to make its way to the theatres. Production costs were phenomenal too. Since it is already drawing only mixed reports from Tamilnadu, the producer isn't going to be happy about reshooting the entire climax scene. Shooting the climax scene would normally cost big money and there still is no assurance that the film will do well at the box office.
They'll then have to run after the stars for their dates. By then, it'd be too late.