I've come across more than one site praising the first season, and hoping for a second season. Elfen Lied was the best anime I've ever seen, even though it was only comprised of 13 episodes.
One of the issues that would be faced by some is how would a second season go? Would it take off where the Manga ended, or where the Anime ended? Because the Anime has events that lead up to about halfway through the Manga, and the Manga itself offers so much more, especially where it comes with Lucy and Kohta. Arakawa (Kakuzawa's partner) is much more influential in the Manga than the Anime.
So the question is what's going to happen with season 2, IF it gets done? I want it so bad!