I liked the show dance and am happy with Louis winning, as I didn't have a strong favourite this year. However, at the start of Strictly, several of my friends, who do not usually watch the programme, did say they would watch this year because of his presence - I.e. a good looking, successful Olympian. As casual viewers, I doubt very much that they would have voted though. Even so, I think he must have had some advantage.
Another advantage he had, as a gymnast, over Victoria Pendleton say, was good core strength, foot pressure and balance. (When I started dancing I found it difficult to maintain ballroom hold for even a few minutes, and to find my centre of gravity. It took me a long time to improve in that area and I still have some problems with the latter.). I think a lot of focus has been on the other celebs' dance experience and Louis's advantages have been somewhat underplayed.
I think Louis did work hard, Isledance, as I think he has that built in work ethic and perfectionism. However, he didn't appear to fall in love with dancing and was quite honest about the Olympics being a more important event in his life (understandably). So I guess he came across as more laid back, but he seems a nice enough guy.