It won't deliver good results cause it takes time for a choreographer to learn and understand the contestant's strength and weakness/ high and low points/ area where the participant is gifted and area where more work needs to be done. Therefore, if choreographers are changed every week or if the celebs are rotated than the choreographers will not get time to understand them and make them properly dance to their tunes.
Also, when non-dancers have to work with difficult steps like aerials and lifts, they have a really hard time if they have not developed a comfort level with their choreographer and it shows. They feel like they would fall off or be dropped and that shows in their performances if they are dancing with someone new. So, a trust is formed while working with the same choreographer every week.
Secondly, with time a bond is forged between a choreo and a celeb where the celeb also gets to understand the work ethic, style and dedication of a choreographer. If the choreographer asks the participant to stay in late or work harder, if the celeb does not reciprocate or understand the choreographer the enterprise would be a failure.
The biggest example of this is:
Baichung Bhutia, a celeb from a non-dance/ non filmy background, but he and his choreo were able to understand and work with each other and ultimately pull it off and WIN. He danced fine with his choreographer but couldn't even dance on 2 steps of Vaibhavi Merchant when he had to dance with her for an opening act I presume.
Edited by -WhisperMahi- - 12 years ago