Recent studies suggest that the future of Match-3 is to offer non-linear progression. This can be done by offering small challenges that take them out of the monotony every few levels. Introducing some kind of long-term objective (and even a bit of scripting) is not a bad idea either.
There are voices that point out that for the genre to survive, among other things, users must be offered many things to play with while the title remains faithful to the original Match-3 idea. No matter how many new features are introduced, those who come to them are looking for a casual experience that offers them a challenge they are already familiar with.