I hope Merlin and Chessy could fix up a bit of paint in some of the areas to make it look fresh again for this season. Apart from the excitement of the rides and attractions, it would certainly make a brighter atmosphere.
It's all about the budgets really. Towards the end of last year a lot of areas were being re-painted such as the Jumbos and the Carousel. The Skyway is also being refurbished, I don't know if that means new trains, but it's something that's really needed.
I don't think a Rapids is in the pipe-line, but I agree that its something would benefit Chessington enormously. The only thing standing in the way is space and where it would go. The grass land next to Pirates Cove is a good location but as Legoland had a Pirate themed rapids built only two years ago, I doubt Merlin would build a similar ride.