Why?
DMK may lose it because they didn't fix corruption and small bribes at government officials. Being the lesser evil is not enough anymore.
Kamal deserves this because he drifted too far away from ethartham and always spoke with amusing word plays. Common people want straight forward, simple sentence constructs.
Change?
But... TVK won't be able to do change much because people themselves are corrupt. They don't want to follow rules as long as they can, when get caught, they are happy to pay bribe. And a lot of people joined TVK were originally from DMK and ADMK who didn't get recognition in their party.
Hope
If the trend continues TVK will win and if he wins I hope Vijay keeps opposing sneaky BJP policies, especially the 3 language formula and NEP. I'm scared by the attitude of Vijay fans though. They are the bigger bullies online, will they take it to street after this win? I don't know.