Since it is only from a voice actor and we know from past experiences that they have been wrong in the past don't consider this confirmation of April. It is definitely a good sign that after so long without a mention of a date and post Nick Upfront April has been mentioned.
Janet Varney will be attending MatsuriCon 2013 tomorrow March 29th and I believe there is going to be a panel with her. So we MAY, emphasis on may get some news.
It makes sense as a date as it would be a year on from Book 2, but we have heard nothing but "It's not done yet" which suggest it will come later. Nick need to put out a trailer or something ASAP if this is true, as this means we are just weeks away, if true. I am definitely not going to put complete faith in this news, but it definitely makes me feel better about the release date.
Thoughts on this glimmer of hope ?