As I said back in the winter, I really enjoyed this. It did something different with the genre, which, while it bothered some, does make it stand out.
As for a sequel, the BBC series, In the Flesh
could provide an example of where a sequel could go, though, tonally, they are very different. However, the reintegration of the living with the "partially dead" (to steal the term from In the Flesh
) could have been more difficult than the ending of Warm Bodies