Does Kaththi need two Vijays?

While Kaththi it's doing great business at the box office and almost the entire media is unanimously praising it as a week made entertainer, one thing about the movie leaves a lingering doubt in my mind. Why are there two Vijays in the movie. Except for the marquee value of having Vijay playing a double role there really doesn't seem to be a necessity for two characters. Yes, we have to admit that the two characters are completely different from each other and that Kathiresan is able to accomplish what Jeevanandam might never have with his methods. But my question is why did there have to be a Jeevanandam and then bring Kathiresan to pose as Jeevanandam. Would the movie have been any different if there had been only one Vijay, named Kathiresan or Jeevanandam, having the qualities of Kathiresan?

Kaththi is focused on the right lead by Kathiresan to bring justice to the village. The double role card played by Murugadoss doesn't have any  significance in the plot. It does not carry any suspense because it is revealed to its right at the start, it does not serve as a turning point at any portion of the film, nor does it cause any major confusion to the characters in the film itself. The only instance where the double role factor has any impact is in the one scene where the antagonists discover that the person they are dealing with is not Jeevanandam, but someone who has taken his place. But even that moment turns out to be of little consequence in the subsequent events and hence the question to Murugadoss; why did you bring in two Vijays?

We all love to see Vijay on screen, especially when he died something new and different on screen. So natuirally, when we saw that Murugadoss was using him in a double role, we think that there is something special in store. But, what we get is a rather underplayed Vijay who is replace very early in the first half by the normal exuberant and energetic Vijay, who then proceeds to do what Vijay does in most of his films, which is sing, dance, fight and emote like only he can. What makes Kaththi good is the fact that it has a solid screenplay and great social relevance, which takes it a notch above a regular 'Vijay' movie.

. So naturally, when we saw that Murugadoss was using him in a 

The double role, I believe, is an unnecessary burden on the screenplay which helps only to add a prologue and an epilogue to an interesting story. The central plot in itself was good enough to make a good movie without resorting to this redundant gallery show, and yet Murugadoss chose to do so, which is puzzling. The double role in Kaththi somehow reminds me of the double role played by the villain of Ghajini, which was a jarring note in an otherwise fantastic movie. Now, the double role in Kaththi is not nearly as bad, but one only feels that it could have been avoided. Please do not take this comment as one that says that Kaththi is a bad movie. It is an immensely enjoyable entertainer with social relevance. The double role however seems to be an unnecessary appendage. What do you think? Please let me know.