Yeah. The ending surely felt lacking. I felt during the beginning of the show and still towards the end they were building something nice and major here to top the still somewhat stunted events of the first season (like building a real meaning for these gates - if the end of the world through Izanami and Izanagi could be called such). However, it really seemed like they threw most of their original ideas and the plot threads they had already developed to the trash can and instead went with something else in the last two episodes.

It was also a bit sad story with Suou dying. Granted, she was a copy to begin with, but like Hei said, she was the current Suou and had been for a while, living her own life and gathering her own memories. Simply creating another copy on another Earth hardly means anything. A different soul, to use such a concept to sum the personality, memories, experiences and everything that make a person in addition to the body and DNA.