Heard about this when my older brother looked Koji Igarashi up on Twitter. I was shocked to hear the news myself, but not necessarily surprised. It seems a lot of the major figures in video game development in Japan (Hideki Kamiya, Shinji Mikami, Keiji Inafune) have been leaving in the past few years. I remember Mikami saying that he left Capcom because it simply wasn't fun to work there anymore. With there not being any sufficient talent to replace them, look where Capcom and Konami are at.
Either way, while I'm not sad to see that we won't be getting a 1999 game, I do think that, had Igarashi been given better opportunities while working at Konami, we could have seen better Castlevanias than what we got. Makes me wonder about games like Curse of Darkness. Could that game had been rushed due to one of the DS (POR, I believe) titles coming out the same year? It's not unreasonable to think there was some kind of development hell similar to what seemed to happen with LOS2. (although LOS2 turned out much better, IMO) Either way, one can only hope that we can get a good Metroidvania, as, while the handheld entries ranged from good to "meh...," the thought of a good 2D "Castlevania" on consoles with HD graphics and excellent gameplay is something that I would love to see become reality.
One can only wish Igarashi luck in all of his future endeavors at this point!